TY - JOUR A1 - Altmann, Korinna A1 - Braun, Ulrike A1 - Bannick, C.-G. A1 - Bednarz, M. A1 - Herper, D. A1 - Knefel, M. T1 - TED-GC/MS: Schnelle Bestimmung von Mikroplastik-Massegehalten in verschiedenen Proben N2 - Zur Ermittlung von Mikroplastik-Gehalten in verschiedenen Umweltmatrices ist ein schnelles Detektionsverfahren für die Routineanalytik notwendig. Ein solches Verfahren wird hier in Form der ThermoExtraktion/Desorption-GasChromatographie/ MassenSpektroskopie (TED-GC/MS) vorgestellt. Neben grundlegenden verfahrensspezifischen Erläuterungen zur Identifizierung und Quantifizierung von Mikroplastik werden auch exemplarische Beispiele aus unterschiedlichen Umweltkompartimenten und Produkten dargestellt. Neu vorgestellt wird ein neues Verfahren zur Analytik von Flaschenwasser. Dazu wurde ein Messfiltertiegel entwickelt, der besonders für Proben mit geringen Gehalten an abfiltrierbaren Stoffen geeignet ist KW - Mikroplasik KW - Mikroplastik-Analyse KW - TED-GC/MS KW - Thermoanalytische Verfahren KW - Mikroplastik-Massengehalte PY - 2020 VL - 2020 IS - 02 SP - 55 EP - 57 PB - Gesellschaft Deutscher Chemiker (GDCh) CY - Frankfurt am Main AN - OPUS4-50835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - BAM activities on microplastics N2 - The presentation is about BAM's activities on the topic of microplastics. It describes what BAM has done in this field in recent years. On the one hand, TED-GC/MS is presented as an analytical method, on the other hand, currently available microplastic reference materials are presented. T2 - JRC/BAM Workshop on ILC CY - Online meeting DA - 11.02.2021 KW - Microplastic KW - TED-GC/MS KW - Microplastic particles KW - Reference materials PY - 2021 AN - OPUS4-52120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Hahn, Marc Benjamin T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. KW - BioSAXS KW - Bio-SAXS KW - Cosolute KW - Ectoine KW - G5P KW - GVP KW - Radiation damage KW - Radical Scavenger KW - Single-stranded DNA-binding proteins KW - X-ray scattering KW - DNA KW - ssDNA KW - Protein KW - SAXS KW - Small-angle xray scattering KW - McSAS3 KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - Geant4-DNA KW - Topas KW - Topas-MC KW - Monte-Carlo simulations KW - Particle scattering simulations KW - Topas-nBio KW - OH Radical KW - OH radical scavenger KW - LEE KW - Ionizing radiation damage KW - Protein unfolding KW - Ectoin PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568909 DO - https://doi.org/10.1039/d2cp05053f SN - 1463-9076 SN - 1463-9084 VL - 25 IS - 7 SP - 5372 EP - 5382 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-56890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Smales, Glen Jacob A1 - ZhuoQing, Li A1 - Yildirim, Arda A1 - Wuckert, E. A1 - Eutionnat, S. A1 - Demel, F. A1 - Huber, P A1 - Lasachat, S. A1 - Schönhals, Andreas T1 - Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion N2 - We study the molecular mobility and electrical conductivity of a homologous series of linear shaped columnar ionic liquid crystals ILCn, (n = 8, 10, 12, 14, 16) using broadband dielectric spectroscopy (BDS), specific heat spectroscopy (SHS), and X-ray scattering. We aim to understand how the alkyl chain length influences the dynamics and electric conductivity in this system. Two dielectrically active relaxation modes are observed, the γ and the αcore process, that correspond to the localized fluctuations of the alkyl chains and cooperative motions of the aromatic core in the columns, respectively. Both the γ relaxation and the αcore process slow down with increasing alkyl chain length. SHS reveals one relaxation process, the αalkyl process that has a similar temperature dependence as that of the αcore process for ILC12, 14, and 16 but shifts to higher temperature for ILC8 and 10. For ILC12, 14, and 16, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. For ILC8 and 10, the DC conductivity behavior is similar to ionic liquids, where the conductivity is coupled with structural relaxation. Small-angle X-ray investigations reveal that both the intercolumnar distance and the disorder coherence length increase with alkyl chain length; conversely, the DC conductivity decreases monotonically. KW - Ionic Liquid Crystals PY - 2022 DO - https://doi.org/10.1021/acs.jpcc.2c03023 SN - 1932-7447 VL - 126 IS - 27 SP - 10995 EP - 11006 PB - ACS AN - OPUS4-55194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hallier, Dorothea C. A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Hahn, Marc Benjamin T1 - Inside back cover for the article "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine" N2 - Showcasing research from the Federal Institute for Material Research and Testing Berlin and Fraunhofer Institute for Celltherapy and Immunology Branch Bioanalytics and Bioprocesses Potsdam. Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine. We aimed to increase the possible undisturbed exposure time during bio-SAXS measurements of single-stranded DNA-binding proteins. Therefore small angle X-ray scattering was performed on Gene-V Protein (G5P/GVP), which is involved in DNA repair processes. To achieve this, irradiations were performed in presence and absence of the hydroxyl-radical scavenger and osmolyte Ectoine, which showed efficient radiation protection and prevented protein aggregation, thus allows for a non-disturbing way to improve structure-determination of biomolecules. KW - Bio-SAXS KW - BioSAXS KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - G5P KW - GVP KW - Geant4 KW - Geant4-DNA KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Protein KW - Protein unfolding KW - Radiation damage KW - Radical Scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas-MC KW - Topas-nBio KW - TopasMC KW - X-ray scattering KW - Particle scatterin simulations KW - ssDNA PY - 2023 DO - https://doi.org/10.1039/D3CP90056H SN - 1463-9076 SN - 1463-9084 VL - 25 IS - 7 SP - 5889 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-57006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz T1 - Confinement induced Relaxations and phase behvaiour of nanoconfined Ionic Liquid Crystal N2 - Ionic Liquid Crystals (ILCs) are materials that combine the properties of liquid crystals together with ionic conduction. It is known that liquid crystal mesophases in confinement exhibit anomalous dynamics and phase behavior. However, similar studies about factors that control the macroscopic properties of ILCs in confinement are limited. Here, Broadband Dielectric Spectroscopy (BDS), X-ray scattering, and calorimetry were applied to study the molecular dynamics, and phase behavior of a guanidinium based columnar ionic liquid crystal confined in self-ordered alumina oxide nanopores of pore sizes ranging from 180 nm down to 25 nm. It is aimed to understand how pore size and pore surface wettability (hydrophilic or hydrophobic) influence the molecular dynamics, and phase behavior for this system which are crucial for applications. The DSC measurements show: (i) the crystalline-liquid crystalline transition temperature has non-monotonic dependence on inverse pore diameter and (ii) the liquid crystalline-isotropic transition is completely suppressed for all the confined samples. This thermally suppressed transition was detected by BDS and X-ray scattering and is considered as a continuous phase transition instead of a discontinuous first order transition. BDS investigations reveal several relaxation processes for the bulk and confined scenarios. The relaxation modes are suppressed and become slower for the confined scenarios compared to the bulk. Possible molecular origins for these relaxation processes are discussed, and it is shown that the self-assembly of these ILCs is dynamic in nature. T2 - CONFIT 2022 CY - Grenoble, France DA - 10.10.2022 KW - Ionic Liquid crystals KW - Nanoconfinement KW - Conductivity PY - 2022 AN - OPUS4-57339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Extending Bio-SAXS measurements of Single-Stranded DNA-Binding Proteins: Radiation Protection of G5P by Cosolutes N2 - Small-angle X-ray scattering (SAXS) can be used for structural de- termination of biological macromolecules and polymers in their na- tive states. To improve the reliability of such experiments, the re- duction of radiation damage occurring from exposure to X-rays is needed.One method, is the use of scavenger molecules that protect macromolecules against radicals produced by radiation exposure.In this study we investigate the feasibility to apply the compatible solute, osmolyte and radiation protector Ectoine (THP(B)) as a scavenger throughout SAXS measurements of single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). Therefore we monitor the radiation induced changes of G5P during bio-SAXS. The resulting microscopic energy-damage relation was determined by particle scattering simu- lations with TOPAS/Geant4. The results are interpreted in terms of radical scavenging as well as post-irradiation effects, related to preferential-exclusion from the protein surface. Thus, Ectoine provides an non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. T2 - MultiChem Conference 2023 CY - Prague, Czech Republic DA - 26.04.2023 KW - Bio-SAXS KW - BioSAXS KW - Compatible solute KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - Ectoin KW - G5P KW - GVP KW - Geant4 KW - Geant4-DNA KW - Gene five protein KW - Hydroxyectoine KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Osmolyte KW - Particle scattering simulations KW - Protein KW - Protein unfolding KW - Proteins KW - ROS KW - Radiation damage KW - Radical Scavenger KW - Radical scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas KW - Topas-MC KW - Topas-nBio KW - X-ray scattering KW - ssDNA KW - Median lethal energy deposit PY - 2023 AN - OPUS4-57407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - BP150: Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. T2 - DPG Frühjahrstagung CY - Dresden, Germany DA - 26.03.2023 KW - Bio-SAXS KW - BioSAXS KW - Compatible solute KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - G5P KW - GVP KW - Gene five protein KW - Geant4 KW - Geant4-DNA KW - Hydroxyectoine KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Osmolyte KW - Particle scattering simulations KW - Protein KW - Proteins KW - Protein unfolding KW - ROS KW - Radiation damage KW - Radical Scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas KW - Topas-MC KW - Topas-nBio KW - X-ray scattering KW - Radical scavenger KW - ssDNA PY - 2023 AN - OPUS4-57254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies. T2 - #RSCposter 2023 CY - Online meeting DA - 28.02.2023 KW - Bio-SAXS KW - BioSAXS KW - Cosolute KW - DNA KW - Dosimetry KW - Ectoin KW - Ectoine KW - G5P KW - GVP KW - Geant4 KW - Geant4-DNA KW - Ionizing radiation damage KW - LEE KW - McSAS3 KW - Microdosimetry KW - Monte-Carlo simulations KW - OH Radical KW - OH radical scavenger KW - Particle scattering simulations KW - Protein KW - Protein unfolding KW - Radiation damage KW - Radical Scavenger KW - SAXS KW - Single-stranded DNA-binding proteins KW - Small-angle xray scattering KW - Topas KW - Topas-MC KW - Topas-nBio KW - X-ray scattering KW - ssDNA KW - Osmolyte KW - Hydroxyectoine KW - Compatible solute KW - ROS KW - radical scavenger PY - 2023 UR - https://pubs.rsc.org/en/content/articlehtml/2023/cp/d2cp05053f AN - OPUS4-57064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Kolmangadi, Mohamed Aejaz T1 - X-ray scattering datasets associated with the publication "Molecular Mobility of Polynorbornenes with Trimethylsiloxysilyl side groups: Influence of the Polymerization Mechanism" N2 - X-ray scattering datasets for samples described in the 2022 publication "Molecular Mobility of Polynorbornenes with Trimethylsiloxysilyl side groups: Influence of the Polymerization Mechanism". This dataset includes both raw and processed X-ray scattering data for samples APTCN and MPTCN, alongside background measurements files (BKG). KW - X-ray scattering KW - SAXS KW - MOUSE KW - Membrane polymers KW - Microporous polymers PY - 2023 DO - https://doi.org/10.5281/zenodo.7621204 PB - Zenodo CY - Geneva AN - OPUS4-56972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Kolmangadi, Mohamed Aejaz T1 - X-ray scattering datasets associated with the publication "Side chain length dependent dynamics and conductivity in self assembled ion channels" N2 - X-ray scattering datasets for samples described in the 2022 publication "Side chain length dependent dynamics and conductivity in self assembled ion channels". This dataset includes both raw and processed X-ray scattering data for samples ILC8, ILC10, ILC12, ILC14 and ILC16 alongside background measurement files (BKG). KW - X-ray scattering KW - SAXS KW - MOUSE KW - Columnar ionic liquid crystals KW - Liquid crystals PY - 2023 DO - https://doi.org/10.5281/zenodo.7621358 PB - Zenodo CY - Geneva AN - OPUS4-56973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Hahn, Marc Benjamin A1 - Hallier, Dorothea C. A1 - Seitz, H. T1 - X-ray scattering datasets and simulations associated with the publication "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine" N2 - This dataset contains the processed and analysed small-angle X-ray scattering data associated with all samples from the publications "Bio-SAXS of Single-Stranded DNA-Binding Proteins: Radiation Protection by the Compatible Solute Ectoine" (https://doi.org/10.1039/D2CP05053F). Files associated with McSAS3 analyses are included, alongside the relevant SAXS data, with datasets labelled in accordance to the protein (G5P), its concentration (1, 2 or 4 mg/mL), and if Ectoine is present (Ect) or absent (Pure). PEPSIsaxs simulations of the GVP monomer (PDB structure: 1GV5 ) and dimer are also included. TOPAS-bioSAXS-dosimetry extension for TOPAS-nBio based particle scattering simulations can be obtained from https://github.com/MarcBHahn/TOPAS-bioSAXS-dosimetry which is further described in https://doi.org/10.26272/opus4-55751. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under grant number 442240902 (HA 8528/2-1 and SE 2999/2-1). We acknowledge Diamond Light Source for time on Beamline B21 under Proposal SM29806. This work has been supported by iNEXT-Discovery, grant number 871037, funded by the Horizon 2020 program of the European Commission. KW - SAXS KW - Radiation protection KW - Microdosimetry KW - G5P KW - Ectoine KW - DNA-Binding protein PY - 2023 DO - https://doi.org/10.5281/zenodo.7515394 PB - Zenodo CY - Geneva AN - OPUS4-56811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Kolmangadi, Mohamed Aejaz T1 - X-ray scattering datasets associated with the publication "Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation" N2 - X-ray scattering datasets for samples described in the 2020 publication "Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation". This dataset includes both raw and processed X-ray scattering data for samples PTCHSiO-Pr, Bu, Hx, Oc and De, alongside background measurements files (BKG). This data was collected using the MOUSE project (instrument and methodology). KW - X-ray scattering KW - SAXS KW - MOUSE KW - Alkyls KW - Polymers PY - 2023 DO - https://doi.org/10.5281/zenodo.7614835 PB - Zenodo CY - Geneva AN - OPUS4-56971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo T1 - In situ electron-beam 'melting' (sublimation) of gold microparticles in the SEM N2 - Gold micro particles have been modified in the past using the high power density of a localized electron beam of acceleration voltages above 100 kV as an energy source to transform matter at the sub-micron scale in a transmission electron microscope uses. Here, the e-beam-induced transformation of precursor microparticles employing a low-energy e-beam with an acceleration voltage of 30 kV in a scanning electron microscope is implemented. Under these conditions, the technique can be classified between e-beam lithography, where the e-beam is used to mill holes in or grow some different material onto a substrate, and e-beam welding, where matter can be welded together when overcoming the melting phase. Modifying gold microparticles on an amorphous SiOx substrate reveals the dominant role of inelastic electron-matter interaction and subsequent localized heating for the observed melting and vaporization of the precursor microparticles under the electron beam. Monte-Carlo scattering simulations and thermodynamic modeling further support the findings. T2 - IKZ International Fellowship Award & Summer School 2025 from May 5 to 7, 2025 CY - Berlin, Germany DA - 05.05.2025 KW - Gold Nanoparticle KW - Scanning Electron Microscopy KW - In situ irradiation KW - Thermodynamic modelling KW - Heat Transfer PY - 2025 AN - OPUS4-63256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - Despite significant progress, computational materials design still faces challenges, especially when simulating large systems needed to describe defects, interfaces, or amorphous states with the accuracy of density functional theory (DFT) or beyond.[1] To address these limitations, machine learning (ML) methods have become increasingly popular in recent years. In this talk, I will present how we’ve developed robust data generation strategies that support the creation and benchmarking of new ML models.[2] I’ll focus on methods for large-scale quantum-chemical bonding analysis and workflows for ML interatomic potentials. We’ve shown that quantum-chemical bonding properties can be used in ML models to predict phononic properties.[3] This enables us to validate several expected correlations— such as the link between bonding strength and force constants—on a large scale. Additionally, we’ve built an automated training framework for machine-learned interatomic potentials (autoplex).[4] Initial workflows include random structure searches, which are well-suited for general-purpose potentials, as well as workflows tailored to ML potentials with accurate phonon properties. While atomistic simulations are highly effective for certain material properties, others— like magnetism or synthesizability—remain difficult. In these cases, it’s promising to benchmark established ab initio methods against chemical heuristics or to develop new ML models based primarily on experimental data.[5,6] T2 - SusML (Sustainable Machine Learning Workshop) CY - Dresden, Germany DA - 29.09.2025 KW - Materials Design KW - Materials Acceleration Platforms KW - Automation KW - Workflows KW - Machine Learned Interatomic Potentials KW - Synthesizability KW - Magnetism PY - 2025 AN - OPUS4-64244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bustamante, Joana A1 - Naik, Aakash A1 - Ueltzen, Katharina A1 - George, Janine A1 - Ertural, Christina T1 - Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study. DFT-part N2 - This repository contains computational data supporting the manuscript titled *“Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study”* It includes raw data for vibrational properties, elastic properties and Bonding analysis. KW - DFT KW - QHA KW - Lattice thermal conductivity KW - Grüneisen parameter PY - 2025 DO - https://doi.org/10.5281/zenodo.17399975 PB - Zenodo CY - Geneva AN - OPUS4-64671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bustamante, Joana A1 - Naik, Aakash A1 - Ueltzen, Katharina A1 - Ertural, Christina A1 - George, Janine T1 - Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study. N2 - This repository includes raw data for bonding analysis and lattice thermal conductivity using MLIP-MACE-MP03b, supporting the manuscript “Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study” KW - DFT KW - LOBSTER KW - Lattice thermal conductivity KW - MLIP PY - 2025 DO - https://doi.org/10.5281/zenodo.17397456 PB - Zenodo CY - Geneva AN - OPUS4-64674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stawski, Tomasz A1 - Miliute, Aiste T1 - Structural Refinement of ZrV₂O₇ with Negative Thermal Expansion Using Pair Distribution Function Analysis N2 - This repository contains Python scripts specifically developed for structural refinement of Zirconium Vanadate (ZrV₂O₇), a material known for its negative thermal expansion (NTE). The scripts implement Pair Distribution Function (PDF) analysis to refine crystal structures directly from experimental X-ray diffraction (XRD) data. The refinement workflow is built around the DiffPy-CMI library, enhanced with custom functionalities tailored for ZrV₂O₇ and similar oxide materials. KW - Zirconium vandate KW - Total scattering KW - Pair distribution function KW - Structure refinement PY - 2025 DO - https://doi.org/10.5281/zenodo.15395752 PB - Zenodo CY - Geneva AN - OPUS4-64750 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Grandel, Jonas T1 - Harmonic phonon dataset N2 - Phonon Dataset calculated with DFT PBE and the foundational MACE-MP-0b3 model. The data are presented and discussed in the following publication: https://doi.org/10.1063/5.0297006 KW - Phonon KW - MACE KW - DFT PY - 2025 UR - https://github.com/ACEsuit/mace-foundations PB - GitHub CY - San Francisco, CA, USA AN - OPUS4-64747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naik, Aakash Ashok T1 - Linking quantum chemical bonding analysis descriptors to material property predictions N2 - Examining the bonding between their constituent atoms in crystalline materials has played a vital role in understanding material properties. For instance, low thermal conductivity in materials is typically attributed to its anharmonicity, which has been reported to arise from strong antibonding interactions and local environment distortions. Employing an automated for bonding analysis that we developed, we have generated for ~13000 crystalline compounds such bonding analysis data. To create new descriptors from these data automatically, we extended our package LobsterPy. The curated descriptors span different types, including statistical representations of bonding characteristics for traditional ML algorithms (e.g., random forests), textual descriptions for large language models (LLMs), and structure graphs for graph neural networks (GNNs). These descriptors are then tested by employing them in several state-of-the-art ML algorithms and architectures to predict the mechanical, vibrational, and thermal properties of crystalline materials. Through this work, we are not only able to demonstrate how one can enhance the model’s predictive accuracy by incorporating quantum chemical bonding-based descriptors alongside typical composition and structure-based descriptors, but it also aids in uncovering relationships between bonding and materials properties on a larger scale, which was not possible before. T2 - AI MSE 2025 CY - Bochum, Germany DA - 18.11.2025 KW - Bonding analysis KW - Machine learning KW - Materials Descriptors KW - Force constants PY - 2025 AN - OPUS4-64791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ueltzen, Katharina T1 - Can simple exchange heuristics help us in predicting magnetic properties of solids? N2 - Environmental and scarcity issues of common functional magnetic materials for, e.g., permanent magnets have intensified the search for rare-earth-free alternatives. This challenge is increasingly met by machine learning of magnetic properties of transition-metal compounds. Surprisingly, bond-angle-derived features were not found to be relevant for magnetic structure prediction in previous studies using DFT-computed labels. This contrasts with the Kanamori-Goodenough-Anderson (KGA) rules of superexchange, present in every magnetism textbook. These semiempirical rules predict whether a nearest-neighbor magnetic interaction in insulators is FM or AFM based on the bond angle, orbital symmetry, and orbital occupancy. For some cases, the rules can be simplified further to only consider the bond angle of neighboring magnetic sites (KGA rules of thumb). We review magnetism—bond angle trends within the MAGNDATA database, the largest collection of experimentally determined magnetic structures. Observed trends follow the KGA rules of thumb, and exceptions can be rationalized. In contrast, bond angles in a popular theoretical DFT database show very different trends and do not depend on the magnetic ordering. Building on our analysis, we engineer heuristic-derived features for the machine learning of magnetic structures. We introduce a new, informative label for predicting magnetic structures that can be extended to magnetic sites and structures of arbitrary complexity. We show that features derived from the heuristic are of high importance for this machine learning task. Beyond this, our model enables the prediction of non-collinear magnetic structures. T2 - AI MSE 2025 CY - Bochum, Germany DA - 18.11.2025 KW - Magnetism KW - Machine Learning KW - Materials Design KW - Chemically Complex Materials PY - 2025 AN - OPUS4-64799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zimmermann, Yoel A1 - Bazgir, Adib A1 - Al-Feghali, Alexander A1 - Ansari, Mehrad A1 - Bocarsly, Joshua A1 - Brinson, L Catherine A1 - Chiang, Yuan A1 - Circi, Defne A1 - Chiu, Min-Hsueh A1 - Daelman, Nathan A1 - Evans, Matthew A1 - Gangan, Abhijeet S A1 - George, Janine A1 - Harb, Hassan A1 - Khalighinejad, Ghazal A1 - Takrim Khan, Sartaaj A1 - Klawohn, Sascha A1 - Lederbauer, Magdalena A1 - Mahjoubi, Soroush A1 - Mohr, Bernadette A1 - Mohamad Moosavi, Seyed A1 - Naik, Aakash Ashok A1 - Ozhan, Aleyna Beste A1 - Plessers, Dieter A1 - Roy, Aritra A1 - Schoeppach, Fabian A1 - Schwaller, Philippe A1 - Terboven, Carla A1 - Ueltzen, Katharina A1 - Wu, Yue A1 - Zhu, Shang A1 - Janssen, Jan A1 - Li, Calvin A1 - Foster, Ian A1 - Blaiszik, Ben T1 - 32 examples of LLM applications in materials science and chemistry: towards automation, assistants, agents, and accelerated scientific discovery N2 - Large Language Models (LLMs) are reshaping many aspects of materials science and chemistry research, enabling advances in molecular property prediction, materials design, scientific automation, knowledge extraction, and more. Recent developments demonstrate that the latest class of models are able to integrate structured and unstructured data, assist in hypothesis generation, and streamline research workflows. To explore the frontier of LLM capabilities across the research lifecycle, we review applications of LLMs through 34 total projects developed during the second annual Large Language Model Hackathon for Applications in Materials Science and Chemistry, a global hybrid event. These projects spanned seven key research areas: (1) molecular and material property prediction, (2) molecular and material design, (3) automation and novel interfaces, (4) scientific communication and education, (5) research data management and automation, (6) hypothesis generation and evaluation, and (7) knowledge extraction and reasoning from the scientific literature. Collectively, these applications illustrate how LLMs serve as versatile predictive models, platforms for rapid prototyping of domain-specific tools, and much more. In particular, improvements in both open source and proprietary LLM performance through the addition of reasoning, additional training data, and new techniques have expanded effectiveness, particularly in low-data environments and interdisciplinary research. As LLMs continue to improve, their integration into scientific workflows presents both new opportunities and new challenges, requiring ongoing exploration, continued refinement, and further research to address reliability, interpretability, and reproducibility. KW - Large Language Models KW - Machine Learning KW - Materials Design KW - Bonding Analysis KW - Phonons KW - Thermal properties PY - 2025 DO - https://doi.org/10.1088/2632-2153/ae011a SN - 2632-2153 VL - 6 IS - 3 SP - 1 EP - 34 PB - IOP Publishing AN - OPUS4-64019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Namrata, Jaykhedkara A1 - George, Janine T1 - Atomistic interaction at the solid interface between Li6PS5Cl and Li metal N2 - Solid-state batteries offer higher energy density and improved safety than conventional lithium-ion cells with flammable liquid electrolytes, [1] but poor interfacial compatibility at the solid-electrolyte (SE)|electrode interface, especially with lithium metal anodes, remains a major challenge. [2] To gain a deeper understanding of the structural and chemical factors governing the formation and growth of this interface, we selected Li6PS5Cl (SE) and Li metal anode as prototype materials. In this work, we begin by performing ab initio molecular dynamics accelerated by machine-learning potentials in VASP, to obtain lattice parameters and bulk moduli of the bulk Li6PS5Cl and Li metal phases, thereby quantifying lattice-mismatch strain, compressibility differences, and their thermal evolution. We then analyze the atomic structure and coordination environments at the Li6PS5Cl|Li interface, which is carefully constructed for the [100] orientation for both SE and Li, allowing the lowest possible strain (see Fig. 1). Dominant bonding motifs are identified using Crystal Orbital Hamilton Population [3] analysis via LOBSTER.[4] Radial distribution functions of the interface are compared with those of the respective bulk phases in the 200-400 K range to elucidate temperature-driven structural rearrangements. This combined analysis reveals how interfacial bonding evolves with temperature and provides critical insight into chemical and mechanical stability at the interface. Our findings offer a quantitative framework for correlating bulk properties with interfacial structure, thereby informing the design of more robust SEs and engineering strategies to improve interfacial compatibility. T2 - 12th Workshop “Lithium-Sulfur Batteries” CY - Dresden, Germany DA - 17.11.2025 KW - Solid-state batteries KW - Interface chemistry KW - Machine learning-molecuar dynamics PY - 2025 AN - OPUS4-64804 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust data generation, heuristics and machine learning for designing sustainable materials N2 - Despite advances in computational materials design, simulating large systems—such as defects, interfaces, or amorphous states—with quantum-chemical accuracy remains a major challenge.[1] Machine learning (ML) methods are emerging as powerful tools to overcome these limitations, enabling scalable and accurate modeling beyond traditional quantum-chemical approaches.[2] They also open new avenues for discovering non-toxic, earth-abundant alternatives to existing materials and can be combined with self-driving labs. [3] There are nowadays robust data generation strategies that underpin the development and benchmarking of ML models. [4,5]atomate2 I will focus on such strategies for quantum-chemical bonding analysis and ML interatomic potentials in my talk. Quantum-chemical bonding descriptors can be effectively used in ML models to predict phononic properties. [6] ML interatomic potentials offer a powerful approach for predicting energies, forces, and stresses—but their performance hinges on high-quality training data. Our automated framework, autoplex, enables diverse and scalable training workflows, from random structure searches for general-purpose models to phonon-aware pipelines for high-accuracy predictions.[7] While quantum chemistry excels in many domains, properties like magnetism and synthesizability remain elusive. Here, heuristics or leveraging experimental data for ML offer promising alternatives.[8,9] T2 - Advanced Materials Safety 2025 CY - Dresden, Germany DA - 04.11.2025 KW - Nano Particles KW - Machine Learning KW - Automation KW - Materials Design KW - Sustainability KW - Material Safety PY - 2025 AN - OPUS4-64599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Von der Computerchemie zur Materialinformatik N2 - In dem Vortrag stelle ich meinen Lebenslauf von einem Chemiestudium bis hin zur Materialinformatik vor. Hierbei stelle ich unter anderem Computerchemie und Materialinformatik vor. Das beinhaltet Kurzeinführungen in die Quantenmechanik und das maschinelle Lernen. T2 - Landesseminar Berlin Brandenburg der deutschen Auswahl für die Internationale Chemieolympiade (Schülerwettbewerb) CY - Berlin, Germany DA - 17.10.2025 KW - Materials Design KW - Computational Chemistry KW - Materials Acceleration Platforms KW - Automation KW - Machine Learning Potentials KW - Outreach PY - 2025 AN - OPUS4-64412 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cope, Elana J. A1 - Bustamante, Joana A1 - Johnson, Zöe M. A1 - Lancaster, Alicia A1 - Gurunathan, Ramya A1 - George, Janine A1 - Agne, Matthias T. T1 - Heat capacity estimation of complex materials for energy technologies N2 - The control of heat in energy materials is one of the greatest current engineering challenges. Accurate estimations of heat capacity are key in creating and using materials safely and efficiently. Current models for heat capacity are often limited due to crude estimations of the phonon density of states, which is a key component of the thermodynamic definition of heat capacity. Utilization of a more detailed phonon density of states, which can easily be obtained from machine-learned algorithms, combined with dilation and electronic contributions, yields heat capacity estimations that are 29% better than the widely utilized Debye model and are comparable to state-of-the-art quantum mechanical calculations. The framework and necessary tools for heat capacity estimations demonstrated herein can be built into more detailed models and analyses, such as high-throughput characterization, transport models, or other thermodynamic assessments. Consequently, the so-called vibrational + dilation + electronic (VDE) model of heat capacity developed in this work better enables the informed design of next-generation devices. KW - Materials Design KW - Heat Capacity KW - Machine learning potentials KW - Thermal Management PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645711 DO - https://doi.org/10.1016/j.joule.2025.102054 SN - 2542-4351 VL - 9 IS - 8 SP - 1 EP - 12 PB - Elsevier Inc. AN - OPUS4-64571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Batatia, Ilyes A1 - Benner, Philipp A1 - Chiang, Yuan A1 - Elena, Alin M. A1 - Kovács, Dávid P. A1 - Riebesell, Janosh A1 - Advincula, Xavier R. A1 - Asta, Mark A1 - Avaylon, Matthew A1 - Baldwin, William J. A1 - Berger, Fabian A1 - Bernstein, Noam A1 - Bhowmik, Arghya A1 - Bigi, Filippo A1 - Blau, Samuel M. A1 - Cărare, Vlad A1 - Ceriotti, Michele A1 - Chong, Sanggyu A1 - Darby, James P. A1 - De, Sandip A1 - Della Pia, Flaviano A1 - Deringer, Volker L. A1 - Elijošius, Rokas A1 - El-Machachi, Zakariya A1 - Fako, Edvin A1 - Falcioni, Fabio A1 - Ferrari, Andrea C. A1 - Gardner, John L. A. A1 - Gawkowski, Mikołaj J. A1 - Genreith-Schriever, Annalena A1 - George, Janine A1 - Goodall, Rhys E. A. A1 - Grandel, Jonas A1 - Grey, Clare P. A1 - Grigorev, Petr A1 - Han, Shuang A1 - Handley, Will A1 - Heenen, Hendrik H. A1 - Hermansson, Kersti A1 - Ho, Cheuk Hin A1 - Hofmann, Stephan A1 - Holm, Christian A1 - Jaafar, Jad A1 - Jakob, Konstantin S. A1 - Jung, Hyunwook A1 - Kapil, Venkat A1 - Kaplan, Aaron D. A1 - Karimitari, Nima A1 - Naik, Aakash A. A1 - Csányi, Gábor T1 - A foundation model for atomistic materials chemistry N2 - Atomistic simulations of matter, especially those that leverage first-principles (ab initio) electronic structure theory, provide a microscopic view of the world, underpinning much of our understanding of chemistry and materials science. Over the last decade or so, machine-learned force fields have transformed atomistic modeling by enabling simulations of ab initio quality over unprecedented time and length scales. However, early machine-learning (ML) force fields have largely been limited by (i) the substantial computational and human effort required to develop and validate potentials for each particular system of interest and (ii) a general lack of transferability from one chemical system to the next. Here, we show that it is possible to create a general-purpose atomistic ML model, trained on a public dataset of moderate size, that is capable of running stable molecular dynamics for a wide range of molecules and materials. We demonstrate the power of the MACE-MP-0 model—and its qualitative and at times quantitative accuracy—on a diverse set of problems in the physical sciences, including properties of solids, liquids, gases, chemical reactions, interfaces, and even the dynamics of a small protein. The model can be applied out of the box as a starting or “foundation” model for any atomistic system of interest and, when desired, can be fine-tuned on just a handful of application-specific data points to reach ab initio accuracy. Establishing that a stable force-field model can cover almost all materials changes atomistic modeling in a fundamental way: experienced users obtain reliable results much faster, and beginners face a lower barrier to entry. Foundation models thus represent a step toward democratizing the revolution in atomic-scale modeling that has been brought about by ML force fields. KW - Materials Design KW - Thermal Conducitivity KW - Nanoparticles KW - Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647829 DO - https://doi.org/10.1063/5.0297006 SN - 0021-9606 VL - 163 IS - 18 SP - 1 EP - 89 PB - AIP Publishing AN - OPUS4-64782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hahn, Marc Benjamin T1 - Temperature effects in the Object Oriented Micromagnetic Framework (OOMMF) - OOMMF input parameter files for Tc determination N2 - To simulate the movement of the macroscopic magnetic moment in ferromagnetic systems under the influence of elevated temperatures, the stochastic version of the Landau-Lifshitz (LL) or the Landau-Lifshitz-Gilbert equation with a spin density of one per unit cell has to be used. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion has to be performed. OOMMF sample files MIF) are provided which can be used to determine the Curie temperature for the classical bulk magnets, iron, nickel and cobalt. KW - OOMMF KW - Temperature KW - Micromagnetism KW - Thetaevolve KW - Ferromagnetism KW - Exchange interaction KW - LLG KW - Landau Lifshitz equation KW - Magnetic moment KW - Magnetic nanoparticles KW - Object oriented micromagnetic framework KW - Stochastic Landau Lifshitz Gilbert equation KW - Temperature scaling PY - 2020 DO - https://doi.org/10.26272/opus4-51169 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-51169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hahn, Marc Benjamin T1 - TOPAS cell model with nanoparticles N2 - These files contain cell models for TOPAS/Geant4 and the inclusion of nano particles in particle scattering simulations. A simple spherical cell with nanoparticles can be generated in a fast manner. The user has the option to include the following organelles: nucleus, mitochondria, cell membrane. Additionally nanoparticles can be included in the cytosol and at the surface of the nucleus and/or the mitochondria. The C++ classes in this repository extend the functionality of the TOPAS (http://www.topasmc.org/) Monte-Carlo program, which is itself a wrapper of the Geant4 MCS Toolkit (http://geant4.org). The sourcecode together with examples and scorers are provided. "If you use this extension please cite the following literature: Hahn, M.B., Zutta Villate, J.M. "Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles." Sci Rep 11, 6721 (2021). https://doi.org/10.1038/s41598-021-85964-2 " KW - Monte-Carlo simulation KW - MCS KW - Geant4 KW - TOPAS KW - TOPAS-nBio KW - Dosimetry KW - Nanoparticles KW - Nanoparticle KW - AuNP KW - Gold KW - Microdosimetry KW - Targeted nanoparticle KW - Simulation KW - Particle scattering KW - Cell KW - Nucleus KW - Mitochondria KW - Cancer therapy KW - Radiation therapy PY - 2020 UR - https://github.com/BAMresearch/TOPAS-CellModels UR - https://github.com/MarcBHahn/TOPAS-CellModels DO - https://doi.org/10.26272/opus4-51150 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-51150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hahn, Marc Benjamin T1 - BioSAXS models for TOPAS/Geant4 N2 - Models for TOPAS/Geant4 to estimate the microscopic dose received by biomolecules during bioSAXS experiments. The C++ classes in this repository extend the functionality of the TOPAS (http://www.topasmc.org/) Monte-Carlo program, which is itself a wrapper of the Geant4 MCS Toolkit (http://geant4.org). KW - TOPAS KW - TOPAS-nBio KW - Geant4 KW - Geant4-DNA KW - MCS KW - Microdosimetry KW - Protein KW - Proteins KW - Particle scattering KW - G5P KW - GV5 KW - SAXS KW - Monte-Carlo simulation KW - Dosimetry KW - Micorscopic dose-damage relation PY - 2022 UR - https://github.com/MarcBHahn/TOPAS-bioSAXS-dosimetry DO - https://doi.org/10.26272/opus4-55751 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - George, Janine A1 - Ouellet-Plamondon, Claudiane A1 - Reyes, Kristofer T1 - Introduction to the “Accelerate Conference 2023–2024” themed collection N2 - The collection showcases the ways in which automation, machine learning and robotics are transforming experimental materials science and chemistry into continuous, computationally integrated processes. It features innovations regarding autonomous laboratories, Bayesian optimisation, high-throughput experimentation and computation, and AI-driven literature extraction, which simplify and scale up materials discovery. Together, these works outline a modular, responsible framework for accelerating scientific progress through human-guided, data-driven autonomy. KW - Automation KW - Materials Acceleration Platforms KW - Synthesizability KW - Workflows KW - Large Language Models KW - Ontologies KW - Materials Discovery PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654658 DO - https://doi.org/10.1039/d5dd90057c SN - 2635-098X SP - 1 EP - 2 PB - Royal Society of Chemistry (RSC) AN - OPUS4-65465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Smales, Glen Jacob A1 - Seitz, H. A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Ectoine interaction with DNA: Influence on ultraviolet radiation damage N2 - Ectoine is a small zwitterionic osmolyte and compatible solute, which does not interfere with cell metabolism even at molar concentrations. Plasmid DNA (pUC19) was irradiated with ultraviolet radiation (UV-C at 266 nm) under quasi physiological conditions (PBS) and in pure water in the presence and absence of ectoine (THP(B)) and hydroxyectoine (THP(A)). Different types of UV induced DNA damage were analysed: DNA single-strand breaks (SSBs), abasic sites and cyclobutane pyrimidine dimers (CPDs). A complex interplay between these factors was observed with respect to the nature and occurrence of DNA damage with 266 nm photons. In PBS, the cosolutes showed efficient protection against base damage, whilst in pure water, a dramatic shift from SSB damage to base damage was observed when cosolutes were added. To test whether these effects are caused by ectoine binding to DNA, further experiments were conducted: small-angle X-ray scattering (SAXS), surface-plasmon resonance (SPR) measurements and Raman spectroscopy. The results show, for the first time, a close interaction between ectoine and DNA. This is in stark contrast to the assumption made by preferential exclusion models, which are often used to interpret the behaviour of compatible solutes within cells and with biomolecules. It is tentatively proposed that the alterations of UV damage to DNA are attributed to ectoine influence on nucleobases through the direct interaction between ectoine and DNA. KW - Ectoine KW - DNA KW - Radiation damage KW - Radiation protection KW - SSB KW - DNA damage KW - DNA protection KW - Compatible solute KW - Zwitterion KW - Hydroxyectoine KW - Salt KW - PBS KW - UV absorption KW - DNA strand-break KW - DNA base damage KW - Ectoine UV absorption KW - Ectoine DNA protection KW - Excited states KW - UV irradiation KW - UV-A KW - UV-B KW - UV-C KW - 266nm KW - UV photons KW - Ectoine-DNA binding KW - Raman spectroscopy KW - UV-Vis KW - Radical scavenger KW - OH scavenger KW - Hydroxyl radicals KW - CPD KW - Abasic site KW - Agarose gel electrophorese KW - SYBR gold KW - DNA melting temperature KW - Counterions KW - Preferential exclusion KW - Cancer KW - Therapy KW - UV protection KW - Sunscreen PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505772 DO - https://doi.org/10.1039/d0cp00092b SN - 1463-9076 SN - 1463-9084 VL - 22 IS - 13 SP - 6984 EP - 6992 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-50577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Solomun, Tihomir A1 - Hahn, Marc Benjamin A1 - Smiatek, J. T1 - Raman spectroscopic signature of ectoine conformations in bulk solution and crystalline state N2 - Recent crystallographic results revealed conformational changes of zwitterionic ectoine upon hydration. By means of confocal Raman spectroscopy and density functional theory calculations, we present a detailed study of this transformation process as part of a Fermi resonance analysis. The corresponding findings highlight that all resonant couplings are lifted upon exposure to water vapor as a consequence of molecular binding processes. The importance of the involved molecular groups for water binding and conformational changes upon hydration is discussed. Our approach further Shows that the underlying rapid process can be reversed by carbon dioxide saturated atmospheres. For the first time, we also confirm that the conformational state of ectoine in aqueous bulk solution coincides with crystalline ectoine in its dihydrate state, thereby highlighting the important role of a few bound water molecules. KW - Fermi resonance KW - Ectoine hydration KW - DFT calculations of Raman spectra KW - Position of carboxylate group PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509855 DO - https://doi.org/10.1002/cphc.202000457 SN - 1439-4235 SN - 1439-7641 VL - 21 IS - 17 SP - 1945 EP - 1950 PB - Wiley-VCH CY - Weinheim AN - OPUS4-50985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Silbernagl, Dorothee A1 - Szymoniak, Paulina A1 - Tavasolyzadeh, Zeynab A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - Interpenetrating Polymer Networks with Tuned Thermal and Mechanical Properties by Multiphoton Lithography N2 - Multiphoton lithography (MPL) has recently attracted significant research interest as a versatile tool capable of fabricating 2D and 3D micro- and nanoscopic features with high spatial resolution. The integrity of MPL microstructures, or their ability to respond to external stimuli, is of critical importance. Often, the mechanically flexible micro-objects are expected to be capable of shape morphing, bending, or other motion to ensure their functionality. However, achieving the desired properties of MPL-manufactured micro components for a specific application still remains challenging. In this work, we present new MPL materials based on epoxy-acrylate interpenetrating networks (IPNs). We aim at fabrication 3D microstructures, whose properties can be easily tuned by varying the ratio of the IPN components and fabrication parameters. The studied mixtures consist of polyethylene glycol diacrylate (PEGDA) and cycloaliphatic epoxide functional groups. Consequently, tryarylsylfonium salt and cyclopentanone photoinitiator tailored for MPL were used to ensure cationic and radical polymerization, respectively. The resulting library of 3D microstructures was investigated for their thermal and mechanical properties using highly sensitive space-resolved methods. For the first time, we were able to evaluate the glass transition behavior of 3D MPL microstructures using fast scanning calorimetry. The influence of both IPN composition and fabrication parameters on glass transition temperature and material fragility was demonstrated. AFM force-distance curve and intermodulation methods were used to characterize the micromechanical properties with lateral resolution of the techniques in the range of 1 micron and 4 nm, respectively. The elastic-plastic behavior of the microarchitectures was evaluated and explained in terms of IPN morphology and thermal properties. The fabricated 3D IPN microstructures exhibit higher structural strength and integrity compared to PEGDA. In addition, IPNs exhibit high to full elastic recovery (up to 100%) with bulk modulus in the range of 4 to 6 MPa. This makes IPNs a good base material for modeling microstructures with intricate 3D designs for biomimetics and scaffold engineering. The effects of composition and MPL microfabrication parameters on the resulting IPN properties give us a better understanding of the underlying mechanisms and microfabrication-structure-property relationships. Moreover, our funding supports the further development of IPN systems as versatile and easily tunable MPL materials. T2 - Material Research Society Meeting CY - Boston, Massachusetts, USA DA - 26.11.2023 KW - Multiphoton Lithography KW - Two-photon polymerisatio KW - Interpenetrating polymer network PY - 2023 SP - 1 AN - OPUS4-59382 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Silbernagl, Dorothee A1 - Szymoniak, Paulina A1 - Tavasolyzadeh, Zeynab A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - Interpenetrating networks with tuned thermal and mechanical properties N2 - Multiphoton lithography (MPL), an emerging microfabrication technique, shows great potential in a variety of applications ranging from tissue engineering to soft micro-robotics. Fabricated micro-objects often are expected to undergo shape morphing or bending. Furthermore, ensuring precise property tuning becomes detrimental for the functionality of MPL microstructures. Herein, we present novel MPL materials based on interpenetrating networks (IPNs), which effectively combine the advantages of acrylate and epoxy thermoset systems. A library of 3D MPL IPN microstructures with high 3D structural stability and tailored thermal and micromechanical properties is achieved. MPL laser velocity and fabrication power can be used to tune the morphology and therefore properties of IPN. New IPN microstructures with materials Young's moduli of 4 to 6 MPa demonstrate susceptibility to deformation with high to fully elastic response. Such soft elastic materials hold immense promise within morphable microsystems, soft micro-robotics and cell engineering applications. T2 - RSC Poster conference CY - Online meeting DA - 05.03.2024 KW - Multiphoton lithography KW - Interpenetrating polymer networks KW - AFM PY - 2024 AN - OPUS4-60060 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia T1 - Direct laser writing of mussel inspired polydopamine N2 - Polydopamine (PDA) is one of the simplest and most versatile approaches for forming an excellent binding exterior to confer new functionalities to nearly any material surface. Inspired by nature, it mimics the behavior of mussels and can be easily deposited on virtually all types of inorganic and organic substrates, including superhydrophobic surfaces. Moreover, PDA exhibits high potential for surface modification and diversified secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. PDA has undergone significant expansion in its applications and is one of the most attractive areas within the materials field. Nevertheless, PDA integration in microdevices is still constrained by poor spatial and temporal control of excited deposition methods. Herein, we demonstrate a novel maskless approach for PDA micropatterning based on Direct Laser Writing that overcomes present limitations. The pattern is formed upon exposure of the dopamine solution by light produced by tightly-focused fs NIR laser that scans substrate surface accordingly to the selected pattern design. Neither strong oxidants, metal ions nor adjusting pH to alkaline is required by this technique to perform dopamine polymerization. Our method achieves the PDA micropatterns with the spatial resolution of 0.8 µm, at least an order of magnitude smaller than what is possible with other PDA microplanning techniques. Some examples of PDA patterns are shown in Figure 1. The here introduced PDA deposition technique will uniquely unravel applications of polydopamine and other catecholamine-based mussel-inspired materials in various multifunctional systems and microdevices (e.g., MEMS elements, microfluidics). The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. Moreover, the morphology and thickness of PDA microstructure can be controlled by the laser power and scanning velocity revealing the possibility of fabricating the structures with gradient. In most of the applied conditions the increase of the laser intensity and decrease of the scanning velocity would lead to the thicker PDA pattern. Different morphologies from smooth and bulky-like to grain like has been obtained. PDA was produced in the presence of tris buffer, phosphate buffer and DI water only. We also tested the effect of the solution pH applying pH 6.0, 7.0 and 8.5. Furthermore, the effect of antioxidants and purging of the solution with oxygen and nitrogen was investigated. Summarizing, we could see that the structures could be produced in all the given conditions, however their thickness and quality, morphology and roughness would differ. We did not observe negative impact of the antioxidants and nitrogen purging on the performance of PDA build up indicating that the PDA formation mechanism is different to common autooxidation. The current mechanism is based on the interaction of dopamine molecules with the photoinitiator added to solution as active to DLW laser light component. Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. We also performed facile posts-modification of the PDA surface with protein enzymes like trypsin that was confirmed by XPS. Obtained bioactive pattern could be further integrated in the protein sensing devices. Presented in this work DLW-based microfabrication technique and the possibilities for further PDA surface post-functionalization empowers advanced applications of this material in single-molecule bioassays, sensors and other complex microdevices. T2 - MNE EUROSENSORS CY - Leuven, Belgium DA - 19.09.2022 KW - Polydopamine KW - Two-photon polymerisation KW - Micropatterning PY - 2022 AN - OPUS4-56421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Naik, Aakash A. A1 - Dhamrait, Nidal A1 - Ueltzen, Katharina A1 - Ertural, Christina A1 - Benner, Philipp A1 - Rignanese, Gian-Marco A1 - George, Janine T1 - A critical assessment of bonding descriptors for predicting materials properties N2 - Most machine learning models for materials science rely on descriptors based on materials compositions and structures, even though the chemical bond has been proven to be a valuable concept for predicting materials properties. Over the years, various theoretical frameworks have been developed to characterize bonding in solid-state materials. However, integrating bonding information from these frameworks into machine learning pipelines at scale has been limited by the lack of a systematically generated and validated database. Recent advances in high-throughput bonding analysis workflows have addressed this issue, and our previously computed Quantum-Chemical Bonding Database for Solid-State Materials was extended to include approximately 13,000 materials. This database is then used to derive a new set of quantum-chemical bonding descriptors. A systematic assessment is performed using statistical significance tests to evaluate how the inclusion of these descriptors influences the performance of machine-learning models that otherwise rely solely on structure- and composition-derived features. Models are built to predict elastic, vibrational, and thermodynamic properties typically associated with chemical bonding in materials. The results demonstrate that incorporating quantum-chemical bonding descriptors not only improves predictive performance but also helps identify intuitive expressions for properties such as the projected force constant and lattice thermal conductivity via symbolic regression. KW - Bonding Analysis KW - Machine Learning KW - Symbolic Regression KW - Chemical Understanding KW - Phonons KW - Thermal Conductivity PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655150 DO - https://doi.org/10.48550/arXiv.2602.12109 SP - 1 EP - 28 PB - Cornell University CY - Ithaca, NY AN - OPUS4-65515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fritzsche, Sven A1 - Weimann, Christiane A1 - Pauw, Brian Richard A1 - Sturm, Heinz T1 - 2PP-TestArtifact N2 - This repository contains a test artifact (TA), also called test structure, designed for two-photon polymerization (also known as Direct Laser Writing (DLW) or Two/Multi-photon lithography (2PA/MPA)). Test artifacts can be used to compare structures, to check options used by the slicer, check the state of the 2PP machine itself or to get a construction guidelines for a certain combination of power, velocity and settings. The associated paper can be found here: https://dx.doi.org/10.1088/1361-6501/acc47a General ideas behind the test artifact: 1. optimized for 2PP-DLW 2. should be fast and easy to analyse with optical microscopy or 3. scanning electron microscopy without tilt. 3. short time to fabricate 4. include a reasonable amount of different features 5. bulk and small structures on the substrate KW - Reference structure KW - Calibration structure KW - Test structure KW - Laser writing KW - Two-photon polymerization KW - 3D printing KW - Additive manufacturing KW - Microprinting KW - Multi-photon light structuring PY - 2023 DO - https://doi.org/10.6084/m9.figshare.22285204.v2 PB - Digital Science CY - Cambridge, MA, USA AN - OPUS4-57165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fornacon-Wood, Christoph A1 - Stühler, Merlin R. A1 - Millanvois, Alexandre A1 - Steiner, Luca A1 - Weimann, Christiane A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Paulus, Beate A1 - Plajer, Alex J. T1 - Fluoride recovery in degradable fluorinated polyesters N2 - We report a new class of degradable fluorinated polymers through the copolymerization of tetrafluorophthalic anhydride and propylene oxide or trifluoropropylene oxide which show up to 20 times quicker degradation than the non-fluorinated equivalents and allow for fluoride recovery. KW - Fluoropolymers KW - Recycling KW - PFAS KW - AFM force distance curves KW - AFM plastic deformation KW - AFM friction analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606768 DO - https://doi.org/10.1039/d4cc02513j VL - 60 SP - 7479 EP - 7482 PB - Royal Society of Chemistry AN - OPUS4-60676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Kittner, Maria T1 - Entwicklung eines Konzeptes zur verbesserten Abbaubarkeit von Polymeren unter realitätsnahen Umweltbedingungen N2 - Das Ziel dieses Grundlagenforschungsprojektes war, die Abbaubarkeit syntheti-scher Polymere unter realitätsnahen Umweltbedingungen durch eine Mischung bzw. Blend eines Hydrolyse- mit einem Oxidations-empfindlichen Polymer zu verbessern, während er unter Nutzungsbedingungen stabil sein sollte. Die Arbeits-hypothese war, dass sich die Polymere gegenseitig in ihrem Abbau beschleunigen, wenn sie der alternierenden Wechselbeanspruchung aus UV-Strahlung und hydrolytischer Beanspruchung ausgesetzt sind. Hierfür wurden vier Blends aus Polylactid (PLA) und Polystyrol (PS) oder Polymethylmethacrylat (PMMA) in unterschiedlichen Mischverhältnissen und Phasenstrukturen mittels additiver Fertigung hergestellt. Die Blends wurden über acht Wochen bei 45 °C mittels alternierender Wechselbeanspruchung aus je fünf Tagen UV-Bestrahlung und zwei Tagen hydrolytischer Beanspruchung beschleunigt gealtert. Für eine Basis-charakterisierung und als Vergleichsgrundlage wurden zusätzlich die Ausgangs-polymere PLA, PS und PMMA jeweils einzeln der hydrolytischen Beanspruchung, UV-Beanspruchung und alternierenden Wechselbeanspruchung unterzogen. Neben der Bestimmung der physiko-chemischen Effekte auf Prüfkörperoberflächen und Bulk wurden erstmalig auch die Wassermedien auf Mikroplastikgehalte und ökotoxikologische Wirkungen analysiert. Die Ergebnisse ergaben, dass reines PLA kaum degradierte, aber der PLA-Abbau sowohl durch Mischung mit PS als auch PMMA verstärkt wurde. Entgegen der Hypothese wurde dadurch allerdings sowohl die Degradation von PS als auch von PMMA gehemmt. Es konnte gezeigt werden, dass sich PS und PMMA im Blend mit PLA durch radikalische Depolymerisation abbauten und die dabei entstehenden Radikale die PLA-Hydrolyse beschleunigten, was wiederum den Abbau der PS- und PMMA-Phasen verlangsamte. Die Ergebnisse zeigten, dass bei dem PLA/PS-Schichtblend (PLA/PS-50) der höchste PS-Gehalt von 50 % den stärksten Effekt auf den PLA-Abbau hatte. Insgesamt war allerdings selbst in diesem Fall die PLA-Degradation nach achtwöchiger Beanspruchung als gering einzustufen. Der totale Masseverlust von PLA/PS-50 entsprach nach achtwöchiger Wechselbeanspruchung -2,6 ± 0,2 mg absolut bzw. ca. -1,5 ± 0,1 % der Prüfkörpermasse, wovon 0,001 % in partikuläres Mikroplastik fragmentierte (PLA: 0,2 – 2,7 μg/g; PS: 3,0 – 3,4 μg/g). Folglich war der größte Teil des Masseverlustes der Prüfkörper auf die Bildung gelöster und/oder gasförmiger Degradationsprodukte zurückzuführen. Ferner zeigten ökotoxikologische Untersuchungen der wechselbeanspruchten Wassermedien von PLA/PS-50 eine zunehmende Hemmung des Algenwachstums der Grünalge Desmodesmus subspicatus, die nach sechs Wochen Wechsel-beanspruchung zu 100 % Hemmung und nach acht Wochen zu einem Absterben der eingesetzten Algenzellen führte. Ergänzende Algenwachstumshemmungstests mit 2 Prüfkörpern der Ausgangspolymere PLA und PS zeigten, dass dies nicht auf der Bildung von partikulärem Mikroplastik, sondern gelösten PS-Degradations-produkten basierte, wie z. B. Benzaldehyd oder Benzoesäure. Zusammenfassend lässt sich sagen, dass nur eine geringe Beschleunigung des PLA-Abbaus bei gleichzeitiger Hemmung des PS- bzw. PMMA-Abbaus stattfand - und das auch erst bei hohen PS- bzw. PMMA-Gehalten. Weiterführende Experimente zeigten, dass dies speziell für PS höchst bedenklich und nicht empfehlenswert ist, da es abhängig von der Konzentration der gelösten PS-Degradationsprodukte zu starken ökotoxikologischen Effekten kommen kann, die von der Hemmung des Algen-wachstums bis zum Algenabsterben reichen können. Folglich konnte die Arbeits-hypothese nur sehr eingeschränkt verifiziert werden und ist mit den hier untersuchten Polymeren als nicht zielführend einzuschätzen. KW - Polymer KW - Blend KW - Microplastik KW - Degradation KW - Umweltsimulation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609879 DO - https://doi.org/10.14279/depositonce-21006 SP - 1 EP - 109 PB - Depostit Once CY - Berlin AN - OPUS4-60987 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waniek, Tassilo A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - The influence of water released from particles in epoxy‐based nanocomposites N2 - AbstractRecent studies have hypothesized that the reinforcing effects of boehmite nanoparticles (BNPs) in polymer nanocomposites (PNCs) are partly related to the particles themselves and partly to the water released from the BNP during curing. In this work, PNCs made from dried BNP (dBNP) with concentrations up to 15 wt% are investigated to differentiate particle and water related effects. The observed trend of the storage modulus in dynamic mechanical thermal analysis measurements was found to be independent of the drying procedure. Stiffness maps from intermodulation atomic force microscopy showed that dBNP leads to a stiffening of the interphase surrounding the particles compared with the unaffected epoxy matrix, while a softer interphase was reported for PNCs with as received BNP. A slight decrease in the glass transition temperature was observed by broadband dielectric spectroscopy related to a lowered crosslink density due to the particles. A significantly higher decrease was reported for PNCs with BNP, attributed to water influencing the curing process. In conclusion, the stiffening of PNC with BNP is related to the particles themselves, while the release of water causes the formation of a soft interphase in the vicinity of the particles and a significant decrease in crosslink density. KW - AFM stiffness of interface KW - Aluminium oxide hydroxide KW - Boehmit nanoparticle KW - Glass transition temperature KW - Broadband dielectric spectroscopy KW - Crosslink density control KW - Structure–property relationship KW - Nanocomposites KW - Thermoset PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606772 DO - https://doi.org/10.1002/app.55937 SN - 0021-8995 SP - 1 EP - 16 PB - Wiley AN - OPUS4-60677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Campbell, C. G. A1 - Jordon Astorga, D. A1 - Dümichen, Erik A1 - Celina, M. T1 - Thermoset materials characterization by thermal desorption or pyrolysis based gas chromatography-mass spectrometry methods N2 - Thermoset materials characterization is often limited to solid state analytical techniques such as IR, NMR, DSC, TGA and mechanical testing. Alternatively, their off-gassing behavior can also be evaluated using GC based techniques such as TD-GC-MS, allowing this method to be applied to thermoset materials analyses such as identification, aging characterization, and formulation optimization. As an overview, common thermoset materials were evaluated by analyzing their gaseous degradation products via TGA-based pyrolysis and subsequent TD-GC-MS for the identification of representative volatile signatures. It is thereby possible to distinguish different classes of phenolic materials or cured epoxy resins, as well as their amine or anhydride curatives. Additionally, this method enabled quantification of a volatile fragment (bisphenol A, BPA) which is associated with oxidation of epoxy/amine thermoset materials. The amount of evolved BPA increased linearly with aging time and this trend exhibits linear Arrhenius behavior over the temperature range (80–125 °C) studied, in agreement with oxidation sensitivies based on oxygen consumption data. Further, TD-GC-MS was used to explore how off-gassing of residual anhydride curative from an epoxy/anhydride material depends on formulation stoichiometry. Even in formulations that theoretically contained enough epoxy to consume all anhydride (1:1 stoichiometry), an imperfect final cure state resulted in residual anhydride which could evolve from the material. For such materials, a slightly epoxy-rich formulation is required to ensure that the material contains no residual unreacted anhydride. Analysis of volatiles generated by thermal exposure is an attractive characterization approach enabling compositional analysis as well as complementary diagnostics for materials degradation. KW - Polymer analysis/characterization KW - Thermal desorption mass spectrometry KW - Thermoset composition KW - Volatiles from thermosets KW - Degradation signatures PY - 2020 DO - https://doi.org/10.1016/j.polymdegradstab.2019.109032 VL - 174 SP - 109032 PB - Elsevier Ltd. AN - OPUS4-50435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Cano Murillo, Natalia A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee A1 - Hahn, Marc Benjamin A1 - Hodoroaba, Vasile-Dan A1 - Sturm, Heinz T1 - Cover image for the article "Nanomechanical study of polycarbonate/boehmite nanoparticles/epoxy ternary composite and their interphases" N2 - The image designed by Natalia Cano Murillo and colleagues shows the cross section of a ternary composite (boehmite/polycarbonate/epoxy, 80μm x 80μm). The surface was measured by AFM kelvin probe microscopy, yielding the surface potential which is shown as 3D‐surface and contour lines. The sample was further subjected to AFM force spectroscopy with a lateral resolution of 1μm², yielding the local Young's modulus, projected in false colors on the 3D surface. The ternary system, containing boehmite nanoparticles, shows a broad distribution of modulus, desirable for optimized macroscopic mechanical properties, such as high stiffness as well as toughness. KW - Boehmite KW - Epoxy KW - Polycarbonate KW - AFM KW - BNP PY - 2020 DO - https://doi.org/10.1002/app.50400 SN - 0021-8995 SN - 1097-4628 VL - 138 IS - 12 SP - 1 PB - Wiley CY - New York, NY AN - OPUS4-51831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia T1 - Micropatterning of mussel-inspired materials - Empower selective functionality N2 - Surface-modification platforms that are universally applicable are vital for the development of new materials, surfaces, and nanoparticles. Mussel-inspired materials (MIMs) are widely used in various fields because of their strong adhesive properties and post-functionalization reactivity. However, conventional MIM coating techniques have limited deposition selectivity and lack structural control, which has limited their use in microdevices that require full control over deposition. To overcome these limitations, we developed a micropatterning technique for MIMs using multiphoton lithography, which does not require photomasks, stamps, or multistep procedures. This method enables the creation of MIM patterns with micrometer resolution and full design freedom and paves the way for innovative applications of MIMs in various multifunctional systems and microdevices, such as microsensors, MEMS, and microfluidics. T2 - BioCHIP Berlin - International Forum on Biochips and Microfabrication CY - Berlin, Germany DA - 28.05.2024 KW - Mussel inspired materials KW - Multiphoton lithography KW - Two photon polymerisation PY - 2024 AN - OPUS4-60254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials. T2 - Workshop on AI in Sustainable Materials Science CY - Düsseldorf, Germany DA - 27.01.2026 KW - Automation KW - Digitalisation KW - Materials Design KW - Thermal Conductivity KW - Chemical bonding KW - Materials Acceleration Platforms PY - 2026 AN - OPUS4-65427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials. T2 - Seminar Gruppe Stephan Roche CY - Barcelona, Spain DA - 22.01.2026 KW - Automation KW - Machine Learning KW - Materials Acceleration Platforms KW - Thermal Conductivity KW - Phonons KW - Bonding Analysis PY - 2026 AN - OPUS4-65428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Janssen, Jan A1 - George, Janine A1 - Geiger, Julian A1 - Bercx, Marnik A1 - Wang, Xing A1 - Ertural, Christina A1 - Schaarschmidt, Jörg A1 - Ganose, Alexander Miguel A1 - Pizzi, Giovanni A1 - Hickel, Tilmann A1 - Neugebauer, Jörg T1 - A Python workflow definition for computational materials design N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron. KW - Worklows KW - FAIR Workflows KW - Automation KW - Materials Acceleration Platforms PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643325 DO - https://doi.org/10.1039/D5DD00231A SN - 2635-098X SP - 1 EP - 14 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia T1 - Direct laser surface micropatterning with polydopamine N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA) is one of the simplest and most versatile approaches to confer new functionalities to nearly any material surface. Moreover, PDA exhibits high potential for surface modification and diversified secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. PDA has undergone significant expansion in its applications and is one of the most attractive areas within the materials field. Nevertheless, PDA integration in microdevices is still constrained by poor spatial and temporal control of excited deposition methods. Herein, we demonstrate a novel maskless approach for PDA micropatterning based on Direct Laser Writing (DLW) that overcomes present limitations. The pattern is formed upon exposure of the dopamine solution by light produced by tightly-focused fs NIR laser that scans substrate surface accordingly to the selected pattern design. Neither strong oxidants, metal ions nor adjusting pH to alkaline is required by this technique. Our method achieves the PDA micropatterns with the spatial resolution of 0.8 µm, at least an order of magnitude smaller than what is possible with other PDA microplanning techniques. The here introduced PDA deposition technique will uniquely unravel applications of polydopamine and other catecholamine-based mussel-inspired materials in various multifunctional systems and microdevices (e.g., MEMS elements, microfluidics). Adjustment of MPL parameters revealed that the morphology and thickness of resulted PDA microstructures can be controlled by altering the laser power and its scanning velocity. As a result, it also enables the production of micropatterns with structural gradient. Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. To ensure post-modification potential of MPL deposited PDA we demonstrated one-step deposition of micropatterns with trypsin. Obtained bio-functionalised surface can be further applied as a protein sensing active microelement. Presented in this work DLW-based microfabrication technique and the possibilities for further PDA surface post-functionalization empowers advanced applications of this material in single-molecule bioassays, sensors and other complex microdevices. T2 - Swiss ePrint 2022 CY - Buchs, Switzerland DA - 05.09.2022 KW - Polydopamine KW - Two-photon polymerisation KW - Micropatterning PY - 2022 AN - OPUS4-56422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dittrich, Maria A1 - Paulo, Carlos A1 - Knabe, Nicole A1 - Sturm, Heinz A1 - Zaitsev, Vladimir A1 - Gorbushina, Anna T1 - Microscopic Raman study of fungal pigment using the genetically amenable rock inhabitant Knufia petricola as a model organism N2 - Fungal pigments such as melanin and carotenoids are distinctive markers of animal and plant pathogenic fungi as well as their environmental relatives. These complex pigments play important roles in pathogenicity and stress tolerance while also being useful as biomarkers. Accordingly, it is important to be able to identify in situ the pigments in black fungi, a group of clinical and environmental importance. In this study, wild-type and genetically modified strains of Knufia petricola A95 and wild fungal cells attached to ancient rock were investigated for their spectroscopic and microscopic Raman features and morphological appearance. Knockout mutants of melanin synthesis genes pks1 (polyketide synthase), sdh1 (scytalone dehydratase), and both pks1 and the carotenoid synthesis gene phd1 (phytoene desaturase) were studied We applied two different Raman microscopes using two lasers, with 633 nm and 488 nm wavelengths. We analyzed and compared Raman spectra between the measured reference substances and the mutant and wild-type strains. In the wild strain WT:A95, the peaks close to melanin peals were found at 1353 cm−1 and 1611 cm−1. There are no characteristic melanin peaks at 1580–1600 cm−1 and around 1350 cm−1 at the spectrum of the Δpks1/Δphd1 mutant and the Δsdh1 mutant. The Δpks1 mutant spectrum has the peaks at the beta-carotene v2 C-C in-plane stretch at 1155 cm−1 and v3 C-CH3 deformation at 1005 cm−1. The peaks of carotenoids and melanin were found in all mutants and the wild strain, except the Δpks1/Δphd1 mutant. Raman spectra allow for discrimination between the various pigments. Hence, interactions between natural fungal melanin, as well as other protective pigments, and complex environmental matrices can be characterized on a range of spatial and temporal scales. KW - Raman Spectroscopy KW - Instrumentation KW - Analytical Chemistry KW - Knufia petricola KW - Confocal microscopy KW - Atomic and Molecular Physics and Optics PY - 2023 DO - https://doi.org/10.1016/j.saa.2023.123250 SN - 1386-1425 VL - 303 SP - 1 EP - 11 PB - Elsevier BV AN - OPUS4-58792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Silbernagl, Dorothee A1 - Szymoniak, Paulina A1 - Tavasolyzadeh, Zeynab A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - Interpenetrating networks with tuned thermal and mechanical properties N2 - Text Multiphoton lithography (MPL) has recently attracted significant research interest as a versatile tool capable of producing 2D and 3D micro- and nanoscopic features with high spatial resolution. The integrity of MPL microstructures, or their ability to respond to external stimuli, is of critical importance. However, achieving the desired properties of fabricated microcomponents for a specific application remains a challenge. In this work, we present new MPL materials based on epoxy-acrylate interpenetrating networks (IPNs). We aim at 3D microstructures, whose properties can be easily tuned by varying the ratio of the IPN components and fabrication parameters (Figure 1). The resulting library of 3D microstructures was investigated for their thermal and mechanical properties using highly-sensitive space-resolved methods. Flash scanning calorimetry revealed the influence of both, IPN composition and fabrication parameters, on glass transition temperature and material fragility. AFM force-distance curve and intermodulation methods were used to characterize the mechanical properties with a lateral resolution of 1 micron and 4 nm, respectively. The deformation, stiffness and elastic behavior are discussed in detail in relation to the morphology. Moreover, we found that some 3D IPN microstructures exhibit fully elastic behavior. Our funding encourages the further development of IPN systems as versatile and easily tunable MPL materials. T2 - Micro Nano Engineering (MNE conference) CY - Berlin, Germany DA - 25.09.2023 KW - Interpenetrating polymer network KW - Multiphoton Lithography KW - Two photon polymerisation KW - Direct laser writing KW - Polyethylene glycol diacrylate PY - 2023 AN - OPUS4-58879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Ectoine protects biomolecules from ionizing radiation: Molecular mechanisms N2 - The compatible solute and osmolyte ectoine is an effective protectant of biomolecules and whole cells against heating, freezing and high salinity. The protection of cells (human Keratinocytes) by ectoine against ultraviolet radiation was also reported by various authors, although the underlying mechanism is not yet understood. We present results on the irradiation of biomolecules (DNA) with ionizing radiation (high energy electrons) in fully aqueous environment in the presence of ectoine and high salt concentrations. The results demonstrate an effective radiation protection of DNA by ectoine against the induction of single strand breaks by ionizing radiation. The effect is explained by an increased in low-energy electron scattering at the enhanced free-vibrational density of states of water due to ectoine, as well as the action of ectoine as an OH-radical scavenger. This was demonstrated by Raman spectroscopy, electron paramagnetic resonance (EPR) and Monte-Carlo simulations (Geant4). T2 - #RSCposter 2023 CY - Online meeting DA - 28.02.2023 KW - Compatible solute KW - Dosimetry KW - Ectoine KW - Ectoin KW - Ectoine radiation protection KW - Ectoine radical scavenger KW - Geant4 KW - Geant4-DNA KW - Hydroxyectoine KW - Hydroxyl radical KW - Ionizing radiation KW - Low energy electrons KW - LEE KW - OH-radical KW - DNA KW - Osmolyte KW - Radiation damage KW - Radiation protection KW - Radical scavenger KW - Radiation therapy PY - 2023 AN - OPUS4-57061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fritzsche, Sven A1 - Pauw, Brian Richard A1 - Weimann, Christiane A1 - Sturm, Heinz T1 - Test artifact for fs-LDW N2 - Data to generate the given graphs in the publication as well as raw images of the shown images. KW - stl code KW - Images KW - Graphs KW - Data PY - 2023 DO - https://doi.org/10.5281/zenodo.7671945 PB - Zenodo CY - Geneva AN - OPUS4-58096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Zarinwall, A. A1 - Waniek, Tassilo A1 - Finke, B. A1 - Sadaat, R. A1 - Sturm, Heinz A1 - Garnweitner, G. ED - Sinapius, M. ED - Ziegmann, G. T1 - Particle Surface Modification N2 - Whilst a decisive role of the particle-matrix interphase on the mechanical properties of nanoparticle-filled polymers has been demonstrated in the last years, the arbitrary design of this interphase remains a very challenging goal. In principle, this could be realized via an appropriate surfacemodification of the nanofiller prior to its incorporation in the polymer. For most systems, such as for boehmite nanofillers, however, the interaction of organic modifiers with the particle surface has not been studied in detail, and only single studies are known rather than systematic investiga- tions on the effects of different chemical functions anchored on the particle surface. In this chapter, we present an extensive study on the binding of APTES, a common silane surface modifier, with boehmite, and show that thermogravimetric analysis (TGA) coupled with mass spectrometry (MS) is a convenient and highly suitable method to elucidate the ligand binding in detail. Furthermore, a two-step coupling strategy is presented, demonstrating that based on APTES anchored to the parti- cle surface, the condensation of various carboxylic acids can be utilized to enable highly diverse chemical properties of the nanofillers, which leads to very different particle-matrix interactions in the nanocomposites. KW - APTES KW - Boehmite KW - Nanoparticle KW - TGA-MS PY - 2021 SN - 978-3-030-68522-5 SN - 978-3-030-68523-2 DO - https://doi.org/10.1007/978-3-030-68523-2 SN - 2194-8240 SN - 2194-8259 SP - 119 EP - 142 PB - Springer Nature Switzerland AG CY - Cham AN - OPUS4-53727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cano Murillo, Natalia A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Sturm, Heinz A1 - Schönhals, Andreas T1 - Electrospun nanocomposites fibers of polycarbonate and taurine modified boehmite nanoparticles - What can be learned from structural and thermal investigations N2 - Though the reinforcing properties of inorganic particles in thermosetting nanocomposites, has been exploited, the integration of nanoparticles continues to be challenging in terms of their homogeneous distribution and their manipulation which can contribute to occupational hazards. Due to a second encapsulations of nanoparticles, electrospun nanocomposite fibers containing nanoparticles might be an alternative for overcoming these issues, as the fiber nonwovens contains the nanoparticles allowing for safer manipulation. Here, the morphology, and the thermal properties of electrospun polycarbonate fibers containing taurine modified boehmite nanoparticles (BNP) are investigated by means of small and wide-angle X-ray scattering as well as fast scanning and temperature modulated fast scanning calorimetry for the first time. The latter techniques allow the investigation of the thermal properties of single fibers at heating rates up to 10^4 K s^-1 keeping its structure intact. A quantitative analysis of the scattering data reveals a porous structure of the fibers. The porous structure is quantified regarding the pore volume and the pore size. A constant amount of aggregation is found even for the highly BNP loaded fibers. Thermal analysis on the fibers reveals a rigid amorphous fraction (RAF) where it is known that RAF determinates the properties of a nanocomposite to a large extent. For the fibers RAF amounts up to 40 wt%, which is essential higher compared to equally formulated PC/BNP composite cast films. The RAF in the case of the fibers, is not only due to the presence of particles in the polymer but also due to orientation effects induced by the electrospinning process. KW - Nanocomposite fibers KW - Electrospinning KW - X-ray scattering KW - Fast scanning calorimetry KW - Rigid amorphous fraction PY - 2021 DO - https://doi.org/10.1021/acsapm.1c01265 VL - 3 IS - 12 SP - 6572 EP - 6585 PB - ACS AN - OPUS4-53871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Schönhals, Andreas A1 - Sturm, Heinz ED - Sinapius, M. ED - Ziegmann, G. T1 - Characterization of Polymer Nanocomposites N2 - The complex effect of nanoparticles on an epoxy-based and anhydride cured DGEBA/Boehmite nanocomposite with different particle concentrations is considered in this chapter. A combination of X-ray scattering, calorimetry (fast scanning and temperature modulated calorimetry) and dielectric spectroscopy was employed to characterize the structure, vitrification kinetics and the molecular dynamics of the nanocomposites. Firstly, the unfilled polymer was found to be intrinsically heterogeneous, showing regions with different crosslinking density, indicated by two separate dynamic glass transitions. Moreover, the glass transition temperature decreases with increasing nanoparticle concentration, as a result of changes in the crosslinking density. In addition, it was shown that the incorporation of nanoparticles can result in simultaneous increase in the number of mobile segments for low nanoparticle concentrations and on the other hand, for higher loading degrees the number of mobile segments decreases, due to the formation of an immobilized interphase. KW - Rigid amorphous fraction KW - Epoxy nanocomposites KW - X-ray scattering KW - Differential scanning calorimetry KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2021 DO - https://doi.org/10.1007/978-3-030-68523-2_4 SP - 55 EP - 77 PB - Springer Nature AN - OPUS4-52698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roszak, I. A1 - Oswald, L. A1 - Ouahabi, A. A. A1 - Bertin, Annabelle A1 - Laurent, E. A1 - Felix, O. A1 - Carvin-Sergent, I. A1 - Charles, L. A1 - Lutz, J.-F. T1 - Synthesis and sequencing of informational poly(amino phosphodiester)s N2 - Sequence-defined poly(amino phosphodiester)s containing main-chain tertiary amines were synthesized by automated solid-phase phosphoramidite chemistry. These polymers were prepared using four monomers with different substituents. The formed polymers were characterized by HPLC and mass spectrometry. These methods evidenced preparation of molecularly-defined polymers. Furthermore, the presence of tertiary amines in the polymer backbones facilitates sequencing by tandem mass spectrometry. KW - Poly(amino phosphodiester) KW - Synthesis KW - HPLC KW - Mass spectrometry PY - 2021 DO - https://doi.org/10.1039/d1py01052b SN - 1759-9954 VL - 12 IS - 37 SP - 5279 EP - 5282 PB - Royal Society of Chemistry AN - OPUS4-53732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zarinwall, A. A1 - Waniek, Tassilo A1 - Saadat, R. A1 - Braun, U. A1 - Sturm, Heinz A1 - Garnweitner, G. T1 - Comprehensive Characterization of APTES Surface Modifications of Hydrous Boehmite Nanoparticles N2 - Hydrous boehmite (γ-AlOOH) nanoparticles (BNP) show great potential as nanoscale filler for the fabrication of fiber reinforced nanocomposite materials. Notably, the particle−matrix interaction has been demonstrated to be decisive for improving the matrix-dominant mechanical properties in the past years. Tailoring the surface properties of the nanofiller enables to selectively design the interaction and thus to exploit the benefits of the nanocomposite in an optimal way. Here, an extensive study is presented on the binding of (3-aminopropyl)triethoxysilane (APTES), a common silane surface modifier, on BNP in correlation to different process parameters (concentration, time, temperature, and pH). Furthermore, a comprehensive characterization of the modified BNP was performed by using elemental analysis (EA), thermogravimetric analysis (TGA) coupled with mass spectrometry (TGA-MS), and Kaiser’s test (KT). The results show an increasing monolayer formation up to a complete surface coverage with rising APTES concentration, time, and temperature, resulting in a maximal grafting density of 1.3 molecules/nm². Unspecific multilayer formation was solely observed under acidic conditions. Comparison of TGA-MS results with data recorded from EA, TGA, and KT verified that TGA-MS is a convenient and highly suitable method to elucidate the ligand binding in detail. KW - Boehmite KW - Nanoparticle KW - Surface KW - APTES KW - Functionalization KW - BET KW - TGA KW - Grafting KW - Nanocomposite KW - Silane PY - 2020 DO - https://doi.org/10.1021/acs.langmuir.0c02682 VL - 37 IS - 1 SP - 171 EP - 179 PB - ACS Publications AN - OPUS4-51954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Hahn, Marc Benjamin A1 - Sturm, Heinz A1 - Bier, F A1 - Solomun, Tihomir T1 - Biologische Konsequenzen einer nanoskaligen Energiedeposition: Fokussierung auf die Rolle niederenergetischer Elektronen T1 - Biological Consequence of Nanoscale Energy Deposition: Focusing on the Role of Low-Energy Electrons N2 - Bei der Behandlung von Krebs mittels Strahlentherapie sollen Tumorzellen abgetötet werden ohne das umliegende gesunde Gewebe zu zerstören. Um Strahlentherapien für Patienten verträglicher zu machen, ist ein besseres Verständnis der zugrundeliegenden Prozesse auf der molekularen Ebene nötig. Dabei sind der Energieeintrag und die Streuprozesse der Strahlung in der Umgebung der DNA von besonderem Interesse. Durch Streuung von hochenergetischer Strahlung in Wasser werden besonders viele Sekundärelektronen mit niedriger Energie erzeugt. Zur Untersuchung der Schädigungseffizienz dieser Elektronen wurde ein Verfahren zur direkten Bestrahlung von Lösungen mittels Elektronen variabler Energien enwtickelt. Dies wurde durch einen neu entwickelten Probenhalter mit einer für Elektronen durchlässigen Nanomembran ermöglicht. Mit diesem können Bestrahlungen an DNA, Proteinen, und Zellen bei verschiedenen pH-Werten oder Salzkonzentrationen durchgeführt werden. Parallel dazu wurde der ortsabhängige Energieeintrag innerhalb des Wassers durch Elektronenstreusimulationen bestimmt. Diese neuartige Kombination von Experiment und Simulation ermöglicht die Bestimmung der Schaden-Dosis-Relation für Elektronenbestrahlung von biologischen Systemen unter realistischen physiologischen Bedingungen. So konnten für die genutzten Primärelektronen wie die mittlere letale Dosis, bei der 50 Prozent der DNA geschädigt sind, mit 1,7 Gy bestimmt. Ebenfalls wurde das für mikrodosimetrische Modellierungen und Betrachtungen der sogenannten Linear energy transfer (LET) Effekte, wichtige Verhältnis von DNA Einzelstrangbrüchen (SSB) zu Doppelstrangbrüchen (DSB) als SSB/DSB = 12/1 bestimmt. Mit Hilfe eines Modells für das Targetvolumen der DNA wurde der mittlere mikroskopische letale Energieeintrag berechnet als E1/2 = 6 ± 4 eV . Es wurde gefolgert, dass weniger als zwei Ionisationsprozesse im sensitiven Targetvolumen der DNA im Mittel zu einem Einzelstrangbruch führen. Diese Methode ist unabhängig von den Primärpartikel und geometrischen Bedingungen. Deshalb ermöglicht sie die Vergleichbarkeit experimenteller Systeme mit inhomogenen Energieverteilungen, welches sonst nicht gegeben ist. Des weiteren wurden die Strahlenschutzfunktionen des Zellschutzmoleküls Ectoines und sein Einfluss auf Wasser und Biomoleküle untersucht. Seine Schutzfunktion gegen ionisierende Strahlung wurde auf die Erhöhung des Streuquerschnitts niederenergetischer Elektronen und seine Eigenschaft als OH-Radikalfänger zurückgeführt. Aufbauend auf unseren Erkenntnissen finden in klinischen Arbeitsgruppen Untersuchungen zu Einsatzmöglichkeiten im Umfeld der Strahlentherapie statt. Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 245767821 N2 - To cure cancer radiation therapy is used to kill tumor cells. It is based on radiation induced damage to biomolecules. Here DNA damage is of key interest due to its central role in apoptosis and mutation. Because of the high amount of water in biological tissue, most of the damage is caused by the secondary particles produced by the inelastic scattering of ionizing radiation and water. A detailed understanding of the underlying molecular processes under physiological conditions is the prerequisite to develop more efficient the-rapies. Therefore irradiations have to be performed in liquid, under consideration of the chemical environment. To make it possible to irradiate liquids with electrons within scanning electron microscopes a new sample holder was constructed incorporating an electron transparent nanomembrane. It makes it possible to irradiate DNA, proteins or cells at different pH and salinity. The median lethal dose for a model system of plasmid DNA and water was determined by the combination of experimental data, particle scattering simulations (Geant4-DNA) and diffusion calculations as D1/2 = 1.7 ± 0.3 Gy. From the convolution of plasmid positions and the spatially resolved energy deposit, as determined by electron scattering simulations, the histogram of the energy deposit within the target volume of the plasmids and the microscopic median lethal energy deposit was calculated as E1/2 = 6 ± 4 eV . It could be deduced, that on average less than two ionization Events are sufficient to cause a single-strand-break. The relation of single-strand-breaks (SSB) to double-strand-breaks (DSB), which is of importance for microdosimetric modeling, was determined as SSB : DSB = 12 : 1. The presented method for the Determination of microscopic dose-damage relations was further extended to be applicable for General irradiation experiments. It is independent of the type of primary radiation used, the experimental geometry, and the diffusional properties of the molecules under investigation. This way different experimental systems with varying, inhomogeneous energy deposit characteristics become comparable with each other, which is not possible when only macroscopic averaged values are taken into account. In addition, the radiation protection properties of the compatible solute Ectoine was investigated. The protective properties of ectoine result from the increase of the inelastic scattering probabilities of low Energy electrons at the acoustic vibrational modes of water and its properties as OH-radical scavenger. Based on our results, further investigations are conducted to evaluate the application of Ectoine in the context of radiation therapy. Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 245767821 KW - Ectoin KW - Ectoine KW - DNS KW - DNA KW - Cancer therapy KW - DNA damage KW - DNA radiation damage KW - Dosimetry KW - DFG KW - Electron irradiation KW - Ectoine DNA interaction KW - Ectoine radiation protection KW - Hydroxyl radicals KW - OH radicals KW - LEE KW - Low energy electrons KW - Microdosimetry KW - Radiation KW - Geant4 KW - Geant4-DNA KW - Radiation therapy KW - LET PY - 2021 UR - https://gepris.dfg.de/gepris/projekt/245767821/ergebnisse?context=projekt&task=showDetail&id=245767821&selectedSubTab=2& SP - 1 EP - 14 AN - OPUS4-52389 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavasolyzadeh, Zeynab A1 - Tang, Peng A1 - Hahn, Marc Benjamin A1 - Hweidi, Gada A1 - Nordholt, Niclas A1 - Haag, Rainer A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential. KW - Direct laser writing KW - Mussel-inspired materials KW - Polyglycerol KW - Polydopamine KW - Micropatterning PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778 DO - https://doi.org/10.1002/smll.202309394 SN - 1613-6829 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Knigge, Xenia A1 - Radnik, Jörg A1 - Sturm, Heinz T1 - Maskless Micropatterning of Polydopamine for versatile surface functionalization N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA has been shown as one of the most versatile platforms for altering the properties and incorporating new functionalities to nearby any material surface despite its nature. Rich chemistry of PDA enables broad variety of surface modification and diverse secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. Despite high potential of polydopamine, the lack of deposition control and precision in existed methods limits their applications in microdevices and miniaturized functional systems like, for example, MEMS, microfluidic and sensorics. Herein, we demonstrate a novel maskless approach for surface micropatterning with polydopamine based on Multiphoton Lithography that overcomes present limitations. Neither strong oxidants, metal ions nor adjustment of pH to alkaline is required by this technique. The spatial resolution down to 0.8 µm has been achieved which is at least an order of magnitude smaller than shown by other existed methods. We are able to control the morphology and thickness of the micropattern by altering fabrication parameters allowing structure gradient. Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. Post-modification of polydopamine micropatterns with protein enzyme like trypsin is demonstrated to highlight its sensing potential. Presented in this work microfabrication technique empowers advanced applications of mussel-inspired materials in single-molecule bioassays, sensors and other complex microdevices. T2 - International Conference on Precision Engineering and Sustainable Manufacturing CY - Okinawa, Japan DA - 18.07.2023 KW - Multiphoton lithography KW - Polydopamine KW - Micropatterning PY - 2023 AN - OPUS4-58878 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Elert, Anna Maria A1 - Chen, Yong-Cin A1 - Smales, Glen Jacob A1 - Topolniak, Ievgeniia A1 - Sturm, Heinz A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Effects of the charge density of nanopapers based on carboxymethylated cellulose nanofibrils investigated by complementary techniques N2 - Cellulose nanofibrils (CNFs) with different charge densities were prepared and investigated by a combination of different complementary techniques sensitive to the structure and molecular dynamics of the system. The morphology of the materials was investigated by scanning electron microscopy (SEM) and X-ray scattering (SAXS/WAXS). The latter measurements were quantitatively analyzed yielding to molecular parameters in dependence of the charge density like the diameter of the fibrils, the distance between the fibrils, and the dimension of bundles of nanofibrils, including pores. The influence of water on the properties and the charge density is studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. The TGA measurements reveal two mass loss processes. The one at lower temperatures was related to the loss of water, and the second process at higher temperatures was related to the chemical decomposition. The resulting char yield could be correlated to the distance between the microfibrils. The DSC investigation for hydrated CNFs revealed three glass transitions due to the cellulose segments surrounded by water molecules in different states. In the second heating scan, only one broad glass transition is observed. The dielectric spectra reveal two relaxation processes. At low temperatures or higher frequencies, the β-relaxation is observed, which is assigned to localized fluctuation of the glycosidic linkage. At higher temperatures and lower frequencies, the α-relaxation takes places. This relaxation is due to cooperative fluctuations in the cellulose segments. Both processes were quantitatively analyzed. The obtained parameters such as the relaxation rates were related to both the morphological data, the charge density, and the content of water for the first time. KW - Cellulose nanofibrils PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600528 DO - https://doi.org/https://doi.org/10.1021/acsomega.4c00255 SN - 2470-1343 VL - 9 SP - 20152 EP - 20166 PB - ACS AN - OPUS4-60052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Pauw, Brian Richard A1 - Weimann, Christiane A1 - Sturm, Heinz T1 - First of its kind: A test artifact for direct laser writing N2 - With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate the high geometrical resolution of fs-LDW structures and the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement. KW - Laser direct writing KW - Multi photon lithography KW - Reference material KW - Raman spectroscopy KW - Confocal raman imaging KW - Slicers KW - Open data on zenodo PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580951 DO - https://doi.org/10.1088/1361-6501/acc47a VL - 34 IS - 7 SP - 1 EP - 14 PB - IOP Science AN - OPUS4-58095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silbernagl, Dorothee A1 - Szymoniak, Paulina A1 - Tavasolyzadeh, Zeynab A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - Multiphoton lithography of interpenetrating polymer networks for tailored microstructure thermal and micromechanical properties N2 - Multiphoton lithography (MPL), an emerging truly 3D microfabrication technique, exhibits substantial potential in biomedical applications, including drug delivery and tissue engineering. Fabricated micro-objects are often expected to undergo shape morphing or bending of the entire structure or its parts. Furthermore, ensuring precise property tuning is detrimental to the realization of the functionality of MPL microstructures. Herein, novel MPL materials based on interpenetrating polymer networks (IPNs) are presented that effectively combine the advantages of acrylate and epoxy systems. IPNs with varying component ratios are investigated for their microfabrication performance and structural integrity with respect to thermal and micromechanical properties. A variety of high-resolution techniques is applied to comprehensively evaluate IPN properties at the bulk, micron, and segmental levels. This study shows that the MPL laser scanning velocity and power, photoinitiator content, and multi-step exposure can be used to tune the morphology and properties of the IPN. As a result, a library of 3D MPL IPN microstructures with high 3D structural stability and tailored thermal and micromechanical properties is achieved. New IPN microstructures with Young’s moduli of 3–4 MPa demonstrate high-to-fully elastic responses to deformations, making them promising for applications in morphable microsystems, soft micro-robotics, and cell engineering. KW - Interpenetrating polymer network KW - Multiphoton lithography KW - Atomic force microscopy KW - Intermodulation AFM KW - Fast scanning calorimetry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600593 DO - https://doi.org/10.1002/smll.202310580 SN - 1613-6810 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-60059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - This talk first introduces students to the Materials Acceleration Platforms and Advanced Materials Characterization at BAM. Then, it motivates high-throuhgput screening for materials discovery and advanced materials simulations based on these core topics. Then four different research studies are presentend: evaluation of generative models, synthesizability prediction via PU learning, acceleration of materials property predictions with bonding analysis and advanced materials simulations supported by automatically trained machine learning potentials. T2 - Guest Lecture in MSE 403/1003, a Seminar in the Curriculum of the University of Toronto CY - Online meeting DA - 13.02.2026 KW - Automation KW - Materials Acceleration Platforms KW - Machine Learning KW - Workflows KW - Phonons KW - Bonding Analysis KW - Thermal Conductivity PY - 2026 AN - OPUS4-65514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Topolniak, Ievgeniia A1 - Elert, Anna Maria A1 - Knigge, Xenia A1 - Ciftci, G. C. A1 - Radnik, Jörg A1 - Sturm, Heinz T1 - High precision micropatterning of polydopamine by Multiphoton Lithography N2 - Mussel-inspired polydopamine (PDA) initiated a multifunctional modification route that leads to the generation of novel advanced materials and their applications. However, existing PDA deposition techniques still exhibit poor spatial control, have a very limited capability of micropatterning and do not allow to locally tune PDA topography. Herein, we demonstrate PDA deposition based on Multiphoton Lithography (MPL) that enables full spatial and temporal control with nearly total freedom of patterning design. Using MPL, we achieve 2D microstructures of complex design with pattern precision of 0.8 μm without the need of a photomask or stamp. Moreover, this approach permits adjusting the morphology and thickness of the fabricated microstructure within one deposition step, resulting in a unique tunability of materials properties. The chemical composition of PDA is confirmed and its ability for protein enzyme immobilization is demonstrated. This work presents a new methodology for high precision and complete control of PDA deposition, enabling PDA incorporation in applications where fine and precise local surface functionalization is required. Possible applications include multicomponent functional elements and devices in microfluidics or lab-on-a-chip systems. KW - Multiphoton lithography KW - Polydopamine KW - Micropatterning PY - 2022 DO - https://doi.org/10.1002/adma.202109509 VL - 34 IS - 18 SP - e2109509 PB - Wiley online library AN - OPUS4-54535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Elert, Anna Maria A1 - Knigge, Xenia A1 - Cifci, G. C. A1 - Radnik, Jörg A1 - Sturm, Heinz T1 - Polydopamine micropatterning for selective substrate bio-functionalization N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA) exhibits strong adhesion to nearly any kind of organic or inorganic surface and shows high ability for surface post-modification and secondary reactions. As a result, PDA has been widely used as a base adlayer to enable versatile surface chemistry and functionalization. It has shown great potential in wide range of applications including biomedical field (e.g., drug delivery, adhesives, photothermal therapy, bone and tissue engineering, cell adhesion, biosensing). However, implementation of PDA in microdevices is still hindered by insufficient spatial and temporal control of excited deposition methods. In this work we present a novel approach to fabricate tunable micropatterned substrates where mussel-inspired chemistry provides base for various surface modification [2]. Current approach applies Multiphoton Lithography (MPL) to initiate local PDA formation, and, therefore, does not require use of microstamp or photomask. As a result, the microstructures of complex designs can be produced with the spatial resolution down to 0.8 μm (Figure 1). The desired design can be easily altered by adjusting the stl model or the fabrication code. Unlike the conventional deposition of PDA based on dopamine auto-oxidation, our method does not require presence of strong oxidants, metal ions or alkaline pH. Herein-demonstrated deposition approach will significantly facilitate applications of polydopamine and other mussel-inspired materials in microdevices and high-resolution active microcomponents (e.g., in MEMS and microfluidics). Adjustment of MPL parameters revealed that the morphology and thickness of resulted PDA microstructures can be controlled by altering the laser power and its scanning velocity. As a result, it also enables the production of micropatterns with structural gradient. Apart from the glass substrate, we performed PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. We tested different composition of dopamine solution for its ability of PDA buildup. Solutions containing Tris buffer, phosphate buffer or DI water only as well as different pH (6.0, 7.0 and 8.5) could be successfully applied for high-precision PDA micropatterning. Moreover, the effect of antioxidants and purging of the solution with oxygen and nitrogen was investigated. In all cases, no decrease of deposition efficiency was observed. The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. To ensure post-modification potential of MPL deposited PDA we demonstrated one-step deposition of micropatterns with trypsin. Obtained bio-functionalised surface can be further applied as a protein sensing active microelement. T2 - Laser Precision Microfabrication CY - Dresden, Germany DA - 07.06.2022 KW - Polydopamine KW - Two-photon polymerisation KW - Micropatterning PY - 2022 AN - OPUS4-55064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fritzsche, Sven T1 - Classification of defects in Direct Laser Writing N2 - Direct laser writing grows to an industry-ready manufacturing platform. A stable quality infrastructure is needed for robust processing. However, flaws, errors or impurities are neither described nor communicated in the community of two-photon polymerization. In contrast, additive manufacturing errors in metals manufacturing are described thoroughly. T2 - MNE EUROSENSORS 2022 CY - Leuven, Belgium DA - 19.09.2022 KW - Quality infrastructure KW - Direct laser writing KW - Two photon polymerisation PY - 2022 AN - OPUS4-55984 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fortini, Renata A1 - Meyer-Plath, A. A1 - Kehren, D. A1 - Gernert, U. A1 - Agudo Jácome, Leonardo A1 - Sturm, Heinz T1 - Measurement of flexural rigidity of multi-walled carbon nanotubes by Dynamic Scanning Electron Microscopy N2 - In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required. KW - Flexural rigidity KW - Bending modulus KW - Resonance frequency KW - Carbon nanotubes KW - Fiber toxicology PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514190 DO - https://doi.org/10.3390/fib8050031 SN - 2079-6439 VL - 8 IS - 5 SP - 31 PB - MDPI AN - OPUS4-51419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silbernagl, Dorothee A1 - Ghasem Zadeh Khorasani, Media A1 - Cano Murillo, Natalia A1 - Elert, Anna Maria A1 - Sturm, Heinz ED - Glatzel, T. T1 - Bulk chemical composition contrast from attractive forces in AFM force spectroscopy N2 - A key application of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, kr) of nanoscopic heterogeneous materials. For a complete structure–property correlation, these mechanical measurements are considered to lack the ability to identify the chemical structure of the materials. In this study, the measured attractive force, Fattr, acting between the AFM tip and the sample is shown to be an independent measurement for the local chemical composition and hence a complete structure–property correlation can be obtained. A proof of concept is provided by two model samples comprised of (1) epoxy/polycarbonate and (2) epoxy/boehmite. The preparation of the model samples allowed for the assignment of material phases based on AFM topography. Additional chemical characterization on the nanoscale is performed by an AFM/infrared-spectroscopy hybrid method. Mechanical properties (kr) and attractive forces (Fattr) are calculated and a structure–property correlation is obtained by a manual principle component analysis (mPCA) from a kr/Fattr diagram. A third sample comprised of (3) epoxy/polycarbonate/boehmite is measured by ImAFM. The measurement of a 2 × 2 µm cross section yields 128 × 128 force curves which are successfully evaluated by a kr/Fattr diagram and the nanoscopic heterogeneity of the sample is determined. KW - AFM force spectroscopy KW - Composites KW - Principle component analysis KW - Structure–property correlation KW - Van der Waals forces PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520175 DO - https://doi.org/10.3762/bjnano.12.5 SN - 2190-4286 VL - 12 IS - 5 SP - 58 EP - 71 PB - Beilstein Institute CY - Frankfurt am Main AN - OPUS4-52017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cano Murillo, Natalia A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee A1 - Hahn, Marc Benjamin A1 - Hodoroaba, Vasile-Dan A1 - Sturm, Heinz T1 - Nanomechanical study of polycarbonate/boehmite nanoparticles/epoxy ternary composite and their interphases N2 - Thermoplastic modified thermosets are of great interest especially due to their improved fracture toughness. Comparable enhancements have been achieved by adding different nanofillers including inorganic particles such as nanosized boehmite. Here, we present a nanomechanical study of two composite systems, the first comprising a polycarbonate (PC) layer in contact with epoxy resin (EP) and the second consisting of a PC layer containing boehmite nanoparticles (BNP) which is also in contact with an EP layer. The interaction between PC and EP monomer is tested by in situ Fourier transformed infrared (FT-IR) analysis, from which a reaction induced phase separation of the PC phase is inferred. Both systems are explored by atomic force microscopy (AFM) force spectroscopy. AFM force-distance curves (FDC) show no alteration of the mechanical properties of EP at the interface to PC. However, when a PC phase loaded with BNP is put in contact with an epoxy system during curing, a considerable mechanical improvement exceeding the rule of mixture was detected. The trend of BNP to agglomerate preferentially around EP dominated regions and the stiffening effect of BNP on EP shown by spatial resolved measurements of Young's modulus, suggest the effective presence of BNP within the EP phase. KW - Composites KW - Mechanical properties KW - Nanoparticles KW - Thermoplastics KW - Thermosets PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515965 DO - https://doi.org/10.1002/app.50231 SN - 0021-8995 SN - 1097-4628 VL - 138 IS - 12 SP - 1 EP - 11 PB - Wiley CY - New York, NY AN - OPUS4-51596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sänger, Johanna Christiane A1 - Pauw, Brian Richard A1 - Sturm, Heinz A1 - Günster, Jens T1 - First time additively manufactured advanced ceramics by using two-photon polymerization for powder processing N2 - Methods and materials are presented here, which enable the manufacturing of fine structures using a 3D-printing method known as two-photon polymerization (2PP). As traditional photolithography methods for structuring ceramic slurries do not function with 2PP, due to light scattering on ceramic particles, a novel water-based photoresist with high ceramic loading of extremely well dispersed ceramic nano particles was developed. This photoresist is basically a ceramic slurry containing a photocurable agent and a photoinitiator to be crosslinkable with the 780 nm wavelength femtosecond laser light source of the 2PP machine. It is demonstrated that it is possible to gain a highly transparent and low viscous slurry suitable for 2PP processing. This work shows the development of the slurry, first printing results and the post-printing processes required to form three dimensional ceramic microstructures consisting of alumina toughened zirconia (ATZ). KW - 3D-printing KW - Two-photon polymerization KW - 2PP KW - Ceramic nano particles KW - Slurry KW - Alumina toughened zirconia KW - ATZ KW - Additive manufacturing KW - SchwarzP cells KW - Nano-ceramic-additive-manufacturing photoresin KW - NanoCAM PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517441 DO - https://doi.org/10.1016/j.oceram.2020.100040 VL - 4 SP - 100040 PB - Elsevier Ltd. AN - OPUS4-51744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cano Murillo, Natalia A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee A1 - Emamverdi, Farnaz A1 - Cacua, K. A1 - Hodoroaba, Vasile-Dan A1 - Sturm, Heinz T1 - Carrier Fibers for the Safe Dosage of Nanoparticles in Nanocomposites: Nanomechanical and Thermomechanical Study on Polycarbonate/Boehmite Electrospun Fibers Embedded in Epoxy Resin N2 - The reinforcing effect of boehmite nanoparticles (BNP) in epoxy resins for fiber composite lightweight construction is related to the formation of a soft but bound interphase between filler and polymer. The interphase is able to dissipate crack propagation energy and consequently increases the fracture toughness of the epoxy resin. Usually, the nanoparticles are dispersed in the resin and then mixed with the hardener to form an applicable mixture to impregnate the fibers. If one wishes to locally increase the fracture toughness at particularly stressed positions of the fiber-reinforced polymer composites (FRPC), this could be done by spraying nanoparticles from a suspension. However, this would entail high costs for removing the nanoparticles from the ambient air. We propose that a fiber fleece containing bound nanoparticles be inserted at exposed locations. For the present proof-of-concept study, an electrospun polycarbonate nonwoven and taurine modified BNP are proposed. After fabrication of suitable PC/EP/BNP composites, the thermomechanical properties were tested by dynamic mechanical analysis (DMA). Comparatively, the local nanomechanical properties such as stiffness and elastic modulus were determined by atomic force microscopy (AFM). An additional investigation of the distribution of the nanoparticles in the epoxy matrix, which is a prerequisite for an effective nanocomposite, is carried out by scanning electron microscopy in transmission mode (TSEM). From the results it can be concluded that the concept of carrier fibers for nanoparticles is viable. KW - Advanced materials KW - Electrospun nanocomposite fiber KW - Nanomechanical charecteisation KW - Nanosafety KW - Epoxy nanocomposites PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528265 DO - https://doi.org/10.3390/nano11061591 VL - 11 IS - 6 SP - 1591 PB - MDPI CY - CH - 4020 Basel, Switzerland AN - OPUS4-52826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waniek, Tassilo A1 - Braun, U. A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - The impact of water released from boehmite nanoparticles during curing in epoxy-based nanocomposites N2 - The enhancing effect on mechanical properties of boehmite (γ-AlOOH) nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro- and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action. With FTIR-spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail. The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation. KW - Spectroscopy KW - Aluminium oxide hydroxide KW - Glass transition temperature KW - Material chemistry KW - Nanocomposites KW - Structure-property relationship PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527202 DO - https://doi.org/10.1002/app.51006 VL - 138 IS - 39 SP - 51006 PB - Wiley Periodicals LLC CY - Hoboken AN - OPUS4-52720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Topolniak, Ievgeniia A1 - Weise, Matthias A1 - Sturm, Heinz T1 - Shape deviations of DLW microstructures in dependency of fabrication parameters N2 - Deep understanding of the effects associated with fabrication parameters and their influence on the resulting structures shape is essential for the further development of direct laser writing (DLW). In particular, it is critical for development of reference materials, where structure parameters are precisely fabricated and should be reproduced with use of DLW technology. In this study we investigated the effect of various fabrication and preparation parameters on the structural precision of interest for reference materials. A well-studied photo-curable system, SZ2080 negative photo-resist with 1 wt.% Michler's ketone (Bis) photo-initiator, was investigated in this work. The correlation between applied laser power, laser velocity, fabrication direction on the deviations in the structure shape were observed by means of white light interferometry microscopy. Moreover, influence of slicing and hatching distances as well as prebake time were studied as function of sample shape. Deviations in the structure form between the theoretically expected and the one detected after DLW fabrication were observed in the range up to 15%. The observed shape discrepancies show the essential importance of fine-tuning the fabrication parameter for reference structure production. KW - Direct laser writing KW - Fabrication parameters KW - Structural precision KW - SZ2080 negative photo-resist KW - White light interferometry microscopy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535906 DO - https://doi.org/10.1088/1361-6439/ac2a14 VL - 31 IS - 12 SP - 1 EP - 8 PB - IOP Science AN - OPUS4-53590 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zou, T. A1 - Nonappa, N. A1 - Khavani, M. A1 - Vuorte, M. A1 - Penttilä, P. A1 - Zitting, A. A1 - Valle-Delgado, J. J. A1 - Elert, Anna Maria A1 - Silbernagl, Dorothee A1 - Balakshin, M. A1 - Sammalkorpi, M. A1 - Österberg, M. T1 - Experimental and Simulation Study of the Solvent Effects on the Intrinsic Properties of Spherical Lignin Nanoparticles N2 - Spherical lignin nanoparticles (LNPs) fabricated via nanoprecipitation of dissolved lignin are among the most attractive biomass-derived nanomaterials. Despite various studies exploring the methods to improve the uniformity of LNPs or seeking more application opportunities for LNPs, little attention has been given to the fundamental aspects of the solvent effects on the intrinsic properties of LNPs. In this study, we employed a variety of experimental techniques and molecular dynamics (MD) simulations to investigate the solvent effects on the intrinsic properties of LNPs. The LNPs were prepared from softwood Kraft lignin (SKL) using the binary solvents of aqueous acetone or aqueous tetrahydrofuran (THF) via nanoprecipitation. The internal morphology, porosity, and mechanical properties of the LNPs were analyzed with electron tomography (ET), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and intermodulation AFM (ImAFM). We found that aqueous acetone resulted in smaller LNPs with higher uniformity compared to aqueous THF, mainly ascribing to stronger solvent−lignin interactions as suggested by MD simulation results and confirmed with aqueous 1,4-dioxane (DXN) and aqueous dimethyl sulfoxide (DMSO). More importantly, we report that both LNPs were compact particles with relatively homogeneous density distribution and very low porosity in the internal structure. The stiffness of the particles was independent of the size, and the Young’s modulus was in the range of 0.3−4 GPa. Overall, the fundamental understandings of LNPs gained in this study are essential for the design of LNPs with optimal performance in applications. KW - Lignin KW - Electron tomography KW - Intermodulation AFM KW - Modulus KW - SAXS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546948 DO - https://doi.org/10.1021/acs.jpcb.1c05319 SN - 1520-5207 VL - 125 IS - 44 SP - 12315 EP - 12328 PB - ACS AN - OPUS4-54694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lackmann, C. A1 - Velki, M. A1 - Šimić, A. A1 - Müller, Axel A1 - Braun, U. A1 - Ečimović, S. A1 - Hollert, H. T1 - Two types of microplastics (polystyrene-HBCD and car tire abrasion) affect oxidative stress-related biomarkers in earthworm Eisenia andrei in a time-dependent manner N2 - Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology. Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms. KW - Microplastics KW - Earthworms KW - Toxicity KW - Biomarker KW - oxidative stress PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545423 DO - https://doi.org/10.1016/j.envint.2022.107190 VL - 163 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-54542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Fritzsche, Sven A1 - Pauw, Brian Richard A1 - Weimann, Christiane A1 - Sturm, Heinz T1 - First of its kind: A test artifact for direct laser writing N2 - With Direct Laser Writing (DLW) maturing in all aspects as a manufacturing technology a toolset for quality assurance must be developed. In this work we want to introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric feature to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. Selective Laser Melting. The test artifact introduced in this work was developed in particular to accommodate 1) the high geometrical resolution of DLW structures and 2) the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our DLW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresist, laser power and scanning speed and to analyse the geometric accuracy of a structure produced using these guidelines. KW - Multi photon lithography KW - Test artifact KW - Two photon polymerization KW - Direct Laser Writing KW - Quality infrastructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560530 DO - https://doi.org/10.20944/preprints202210.0259.v1 SP - 1 EP - 29 PB - MDPI CY - Basel AN - OPUS4-56053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Plajer, A. J. T1 - Thioanhydride/isothiocyanate/epoxide ring-opening terpolymerisation: sequence selective enchainment of monomer mixtures and switchable catalysis N2 - We report a new sequence selective terpolymerisation in which three monomers (butylene oxide (BO) A, PhNCS B and phtalic thioanhydride (PTA) C) are selectively enchained into an (ABA′C)n sequence. PTA/PhNCS/BO ring-opening terpolymerisation ROTERP can be coupled with CS2 ROTERP to generate tetrapolymers and with εDL ROP in switchable catalysis for blockpolymer synthesis. KW - Blockcopolymer KW - 1H-NMR KW - TGA KW - DSC KW - AFM PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552339 DO - https://doi.org/10.1039/d2py00629d SP - 1 EP - 5 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-55233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Near-ambient-pressure Xray photoelectron spectroscopy (XPS) to monitor DNA radiation damage directly in water N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - RADeleven CY - Herceg Novi, Montenegro DA - 19.06.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - ESCA KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydrated electrons KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionisation KW - Ionization KW - LEE KW - DEA KW - DET KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Protein KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - Single-stranded DNA-binding proteins KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray photo electron spectrocopy PY - 2023 AN - OPUS4-57782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gawek, Marcel A1 - Madkour, Sherif A1 - Szymoniak, Paulina A1 - Radnik, Jörg A1 - Schönhals, Andreas T1 - Energy Dependent XPS Measurements on Thin Films of a Poly(vinyl methyl ether)/Polystyrene Blend in Dependence on Film Thickness – Concentration Profile on a Nanometer Resolution to Understand the Behavior of Nanofilms N2 - The composition of the surface layer in dependence from the distance of the polymer/air interface in thin films with thicknesses below 100 nm of miscible polymer blends in a spatial region of a few nanometers is not investigated completely. Here, thin films of the blend poly vinyl methyl ether) (PVME)/polystyrene (PS) with a composition of 25/75 wt% are investigated by Energy Resolved X-ray Photoelectron Spectroscopy (ER-XPS) at a synchrotron storage ring using excitation energies lower than 1 keV. By changing the energy of the photons the information depth is varied in the range from ca. 1 nm to 10 nm. Therefore, the PVME concentration could be estimated in dependence from the distance of the polymer/air interface for film thicknesses below 100 nm. Firstly, as expected for increasing information depth the PVME concentration decreases. Secondly, it was found that the PVME concentration at the surface has a complicated dependence on the film thickness. It increases with decreasing film thickness until 30 nm where a maximum is reached. For smaller film thicknesses the PVME concentration decreases. A simplified layer model is used to calculate the effective PVME concentration in the different spatial regions of the surface layer. KW - Energy dependent XPS KW - Soft X-ray KW - Thin films PY - 2021 DO - https://doi.org/10.1039/d1sm00656h VL - 17 IS - 29 SP - 6985 EP - 6994 PB - The Royal Chemical Society AN - OPUS4-53039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Energy-resolved x-ray photoelectron spectroscopy measurements on the concentration profile of thin blended poly(vinyl methyl ether)/polystyrene films N2 - The composition of thin films of polymer blends in vertical direction is still under discussion. For explaining the thickness dependence of some properties like the thermal glass transition temperature, a three-layer model has been introduced consisting of an adsorbed layer with a reduced segmental mobility at the substrate, a bulk-like layer in the middle of the film and an outermost surface layer with a higher molecular mobility. X-ray photoelectron spectroscopy (ER-XPS) measurements with a varying excitation energy from 400 eV to 1486.6 eV and, herewith, an information depth from 1.5 nm to 10 nm were performed at PVME/PS films with compositions of 25/75 wt% and 50/50 wt% and thicknesses between 15 nm and 190 nm. As expected, it was found that the PVME concentration decreases with increasing information depth. Secondly, a complex correlation between the PVME concentration at the surface and the film thickness was found. The PVME concentration increases with decreasing film thickness until a maximum at 30 nm. For thinner films, the PVME concentration decreases. These data agree with previous investigations obtained with specific heat spectroscopy. We thank BESSY II (HZB) for the allocation of beamtime at the HE-SGM beamline and for technical support. DFG (Project number 124846229) is acknowledged for financial support. T2 - German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities (SNI2022) CY - Berlin, Germany DA - 05.09.2022 KW - X-ray photoelectron spectroscopy KW - Miscible polymer films KW - Depth profiling PY - 2022 AN - OPUS4-55654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - The change of DNA AND PROTEIN radiation damage upon hydration: In-situ observations by near-ambient-pressure XPS N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - Dyson Conference 2023 CY - Prague, Czech Republic DA - 24.04.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - ESCA KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionization KW - Ionisation KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - G5P KW - Protein KW - Single-stranded DNA-binding proteins PY - 2023 AN - OPUS4-57406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hallier, Dorothea C. T1 - An XPS study on X-ray radiation damage: Chemical changes to Gene-V Protein of Bacteriophage M13 N2 - X-ray photoelectron spectroscopy (XPS) is used to analyze the direct damage of ionizing radiation to a single-stranded DNA binding protein: Gene-V Protein (G5P). T2 - Science Day Uni Potsdam Institut für Biochemie und Biologie CY - Potsdam, Germany DA - 11.10.2022 KW - XPS KW - Radiaton damage KW - G5P GVP KW - Single-stranded DNA-binding protein KW - X-ray KW - DNA PY - 2022 AN - OPUS4-56541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - The change of DNA radiation damage upon hydration: In-situ observations by near-ambient-pressure XPS N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - #RSCposter 2023 CY - Online meeting DA - 28.02.2023 KW - Cancer treatment KW - DNA KW - Dosimetry KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - TOPAS KW - TOPAS-nbio KW - particle scattering KW - Simulation KW - Radiolysis KW - Radiation therapy KW - Radiotherapy KW - LEE KW - Low energy electrons KW - MCS KW - Base damage KW - Base loss KW - DNA radiation damage KW - Direct damage KW - Dissociative electron transfer (DET) KW - Dissociative electron attachment (DEA) KW - Double-strand break (DSB) KW - Hydrated DNA KW - Hydrated electron KW - Ionization KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Prehydrated electron KW - Quasi-direct damage KW - Radiation damage KW - Radical KW - Reactive oxygen species KW - ROS KW - Single-strand break (SSB) KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - presolvated electron PY - 2023 UR - https://www.nature.com/articles/s42004-021-00487-1 AN - OPUS4-57063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - The change of dna and protein radiation damage upon hydration: in-situ observations by near-ambient-pressure xps N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. Furthermore, first data about the degradation of single-stranded DNA binding-proteins (G5P / GV5 and hmtSSB) under vacuum and NAP-XPS conditions are presented. T2 - AVS69 CY - Portland, USA DA - 05.11.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - Protein KW - Proteins KW - Geant4 KW - Dosimetry KW - Microdosimetry KW - NAP-XPS KW - Xray photo electron spectrocopy KW - Radiation damage KW - Geant4-DNA KW - G5P KW - GVP KW - Hydroxyl radical KW - LEE KW - DEA KW - DET KW - ROS KW - Prehydrated electron KW - TOPAS KW - Near ambient pressure xray photo electron spectroscopy KW - SSB KW - DSB KW - Single-strand break (SSB) KW - ESCA KW - Single-stranded DNA-binding proteins KW - Reactive oxygen species PY - 2023 AN - OPUS4-58761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Preliminary results of an interlaboratory comparison on microplastics organised by plasticsfate N2 - Microplastics are everywhere in the environment, but analytics is challenging. Since harmonisation is missing as well es suitable reference materials, BAM did under th umbrella of VAMAS funded by the EU Horizon 2020 project PlasticsFate a ILC for microplastic detection methods. Methods adressed were IR, Raman, Py-GC/MS and TED-GC/MS. The talk gives a first presentation and evaluation on the results. T2 - CUSP annual meeting and conference CY - Utrecht, Netherlands DA - 12.09.2023 KW - Microplastics KW - TED-GC/MS KW - Polymer 3R KW - Reference material KW - ILC on detection methods PY - 2023 AN - OPUS4-60036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Giovannozzi, A T1 - Standardization and Harmonization Effort on Microplastics Analysis by Spectroscopic Methods N2 - This talk presents the EU funded project PlasticTrace. It shows the challenges in micro- and nanoplastic reference materials and gives some solutions regarding spectroscipc methods such as Raman or IR microscopy to determine the particle numbers. Materials are prepared by cryo milling to get some powder that is later pressed into tablets. The polymer type used is PET, because that is highly important for drinking water directive of EU commission. T2 - International Conference on Raman Spectroscopy (ICORS) CY - Roma, Italy DA - 28.07.2024 KW - Microplastics KW - Reference materials KW - Polymer 3R PY - 2024 AN - OPUS4-60881 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miliūtė, Aistė T1 - Structural evolution of ZrV2O7: supercell persistence revealing local and global structure duality N2 - In the AM2O7 family of negative thermal expansion materials (NTE), evidence of supercell at room temperature was reported following the Völlenke et al. discovery of missed superlattice due to the apparent linearity of the M-O-M bond in GeP2O7. Korthuis et al. and Khosrovani et al. demonstrated it to be true for cubic ZrV2O7 as well. It was concluded that at room temperature, the structure consists of 27 'subcells' with bent M2O7 groups that appear to form a linear configuration due to refinement of averaged position. However, around 100 °C, the transition to the “parent” cell was reported, where the cell volume increases, and the M-O-M angles are constrained by the Pa-3 space group symmetry to be 180°. We followed structural changes in the ZrV2O7 at high temperatures to demonstrate partial disorder within the crystal, local and global structural duality and supercell persistence at high temperatures. Total scattering measurements and Pair Distribution Function (PDF) analysis revealed that the experimental pattern cannot be fitted with the “parent structure” model, and only the 3×3×3 supercell model can correspond to local and global structures throughout the full 25-700 °C temperature range. We also show how short and long-range order within the crystal changes when approaching the phase transition, which might indicate the existence of coherent structural domains that evolve between order and disorder with increasing temperature. We further hypothesize how this can be related to the negative thermal expansion mechanism and the interpretation of structure solutions presenting data from high-temperature X-ray absorption fine structure (XAFS) and Transmission Electron Microscopy (TEM) measurements. T2 - 5th International Symposium on Negative Thermal Expansion and Related Materials (ISNTE-5) CY - Porto, Portugal DA - 29.07.2025 KW - NTE KW - Ab initio KW - PDF KW - CSM PY - 2025 AN - OPUS4-63874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miliūtė, Aistė T1 - Theoretical and experimental development of negative thermal expansion material ZrV2O7 N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which stands out for its remarkable isotropic unit cell contraction over a broad temperature range (130°C < T < 800°C). This enables the fabrication of composites where the overall expansion coefficient can be tailored to a specific negative, positive, or neutral value. Consequently, such composite materials are attractive for many device applications because they can compensate for damage caused by thermal expansion. They are relevant to optical systems, electronic and biomedical applications. In this study, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation (QHA), temperature-dependent effective harmonic potentials (TDEP)[5]) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. In analytical techniques that can provide structural information such as pair distribution function analysis (PDF), X-ray diffraction (XRD), and Extended X-ray Absorption Fine Structure (EXAFS), molecules and atoms are fit geometrically without consideration of atom interactions. Therefore, in combination with these methods, we also consider potential energy surfaces and conclude what structures are likely to form energetically in the full NTE temperature range, in addition to fitting experimental data geometrically. We also optimise experimentally fitted structures to their lowest energy configurations and re-generate comparative data to observe what differences would be visible experimentally. T2 - XLVIII International Congress of Theoretical Chemists of Latin Expression CY - Cartagena de Indias, Colombia DA - 13.07.2025 KW - NTE KW - Ab initio KW - QHA KW - TDEP KW - anharmonicity PY - 2025 AN - OPUS4-63873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gawek, Marcel A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Growth kinetics of the adsorbed layer of poly(2-vinylpyridine) - An indirect observation of desorption of polymers from substrates N2 - The growth kinetics of the adsorbed layer of poly(2-vinylpiridine) on silicon oxide is studied using a leaching technique which is based on the Guiselin brushes approach. The adsorbed layer is grown from a 200 nm thick P2VP film for several annealing time periods at different annealing temperatures. Then the film is solvent-leached, and the height of the remaining adsorbed layer is measured by atomic force microscopy. At the lowest annealing temperature only a linear growth regime is observed, followed by a plateau. Here, the molecular mobility of segments is too low to allow for a logarithmic growth. At higher annealing temperatures, both linear and logarithmic growth regimes are observed, followed by a plateau. At even higher annealing temperatures, the growth kinetics of the adsorbed layer changes. A linear growth followed by logarithmic growth kinetics is observed for short annealing time periods. For longer annealing time periods, an upturn of the growth kinetics is observed. At the highest annealing temperature, only a logarithmic growth regime is found. The change in the growth kinetics is discussed by an alteration in the structure of the adsorbed layer. Moreover, the interaction between the polymer segments and the substrate becomes weaker due to both enthalpic and entropic effects. Therefore, at high annealing temperatures the polymer segments might more easily desorb from the substrate. KW - Ultra thin polymer films PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575423 DO - https://doi.org/10.1039/d3sm00129f SN - 1744-683X SN - 1744-6848 VL - 19 IS - 21 SP - 3975 EP - 3982 PB - Royal Society of Chemistry (RSC) CY - London AN - OPUS4-57542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ueltzen, Katharina A1 - Naik, Aakash A1 - Ertural, Christina A1 - Benner, Philipp A1 - George, Janine T1 - Software and data repository: Can simple exchange heuristics guide us in predicting magnetic properties of solids? N2 - Software and data for the publication "Can simple exchange heuristics guide us in predicting magnetic properties of solids?" Release that corresponds to the first preprint version of the article. Full Changelog: https://github.com/DigiMatChem/paper-exchange-heuristics-in-magnetic-materials/commits/v1.0.0 KW - Magnetism KW - Machine Learning KW - Materials Design KW - Chemically Complex Materials KW - Sustainable Materials Design PY - 2025 DO - https://doi.org/10.5281/zenodo.16811104 PB - Zenodo CY - Geneva AN - OPUS4-64672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Dynamics of Composite Materials N2 - Historically, to tune the properties of a polymer or more general soft matter systems by a second phase is not a new concept and dates back to the 40s of the last century. Beside some successes, the improvement of the properties remained somehow limited. The expectations of the enhancement of the properties of composites changed by the developments of Toyota Central research in the 1990s. It was shown that the incorporation of 5 vol% exfoliated layers of a clay system into a polymer leads to a strong improvement of the mechanical and thermal properties. This discovery stimulated a broad research interest of both fundamental and applied character. Today, polymer-based nanocomposites have reached a billion-dollar global market. The corresponding applications span from components for transportation, commodity plastics with enhanced barrier and/or flame retardancy characteristics, to polymers with electrical properties for shielding, electronics, sensors, and solar cells as well as to live science. Important fields are filled rubbers, reinforced thermoplastics, or thermosets for automotive, aircraft/space and marine industries, but also membranes for separation processes as well as barrier layers, just to mention a few. For a variety of applications, the molecular mobility in nanocomposites is of great importance. This concerns the molecular mobility needed to form a percolating filler network in rubbers used in tires or in composites employed in electric shielding applications. In general, it is also essential for processing polymer-based nanocomposites. Furthermore, separation processes in composite materials for membranes require a certain molecular mobility. This also concern nanodielectrics used in electrical applications or sensors where the mobility of charge carriers can be related to the fluctuations of molecular groups etc. Finally, the molecular mobility can be taken as probe for structure on a molecular scale. Broadband dielectric spectroscopy is a powerful tool to investigate the molecular mobility in polymer systems. It is due to the extremely broad frequency and sensitivity range that can be covered by this technique. Information about localized and cooperative molecular fluctuations, polarization effects at interfaces, as well as charge transport processes can be deduced. Therefore, this book focusses on broadband dielectric spectroscopy of composite materials. Moreover, the dielectric studies are accompanied by mechanical spectroscopy, advanced calorimetry, NMR techniques, as well as transmission electron microscopy and X-ray scattering investigations. Besides a brief introduction to (nano)composites, the book aims to address fundamental aspects of the molecular mobility in this innovative group of materials. Selected examples with scientific interest and some cases with high industrial impact were chosen. Due to the breadth of the subject, unfortunately not all topics could be addressed in detail, such as processing for instance. Berlin, Andreas Schönhals July 2021 Paulina Szymoniak KW - Composite materials KW - Nanocomposites PY - 2022 SN - 978-3-030-89722-2 SN - 978-3-030-89723-9 DO - https://doi.org/10.1007/978-3-030-89723-9 VL - 2022 SP - 1 EP - 375 PB - Springer Nature CY - Cham, Switzerland AN - OPUS4-54538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Dietrich, P. M. A1 - Radnik, Jörg T1 - In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS xperiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. KW - DNA KW - XPS KW - NAP-XPS KW - Radiation damage KW - Single-strand break (SSB) KW - Double-strand break (DSB) KW - Xray KW - OH radical KW - Hydroxyl radical KW - LEE KW - Low energy electrons KW - Dosimetry KW - Geant4 KW - Geant4-DNA KW - TOPAS KW - TOPAS-nbio KW - Microdosimetry KW - DNA radiation damage KW - Direct damage KW - Indirect damage KW - Quasi-direct damage KW - Hydration shell KW - Dry DNA KW - Hydrated DNA KW - ROS KW - Radical KW - Reactive oxygen species KW - Net-ionization reaction KW - Radiation therapy KW - Cancer therapy KW - Xray photo electron spectrocopy KW - Near ambient pressure xray photo electron spectroscopy KW - Base damage KW - Base loss KW - Dissociative electron transfer (DET) KW - Dissociative electron attachment (DEA) KW - Hydrated electron KW - Prehydrated electron KW - Ionization KW - PES PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524060 DO - https://doi.org/10.1038/s42004-021-00487-1 SN - 2399-3669 VL - 4 IS - 1 SP - 50 PB - Springer Nature CY - London AN - OPUS4-52406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - In-situ monitoring of water dependent DNA and protein radiation damage by near-ambient-pressure XPS N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - ICRR 2023 CY - Montreal, Canada DA - 26.08.2023 KW - DNA KW - XPS KW - Proteins KW - Protein KW - G5P KW - Base damage KW - Base loss KW - Cancer treatment KW - DEA KW - DET KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - ESCA KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydrated electrons KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionisation KW - Ionization KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - Single-stranded DNA-binding proteins KW - TOPAS KW - TOPAS-nbio KW - TopasMC KW - Xray photo electron spectrocopy PY - 2023 AN - OPUS4-58214 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hahn, Marc Benjamin T1 - Behind the paper: Radiation, DNA and water: New techniques for deeper insights N2 - To gain deeper insights into the old questions about the influence of water on radiation interaction with DNA, new spectroscopic techniques had to be applied. KW - DNA KW - DNA radiation damage KW - XPS KW - Geant4 KW - Low energy electrons KW - OH radical KW - Hydrated DNA KW - Hydration shell KW - Double-strand break (DSB) KW - Dissociative electron attachment (DEA) KW - Single-strand break (SSB) KW - LEE KW - PES KW - Ionization KW - Reactive oxygen species KW - ROS KW - Base damage KW - Base loss KW - Cancer therapy KW - TOPAS KW - TOPAS-nbio PY - 2021 UR - https://go.nature.com/3gjZVWG SP - 1 EP - 3 PB - Springer Nature CY - London AN - OPUS4-52461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Near-ambient-pressure XPS as as tool to monitor DNA radiation damage directly in water N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - Miller Conference CY - Furiani, France DA - 03.06.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - ESCA KW - Energy deposit KW - G5P KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydroxyl radical KW - Indirect damage KW - Ionisation KW - Ionization KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Particle scattering KW - Prehydrated electron KW - Presolvated electron KW - Protein KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - Single-stranded DNA-binding proteins KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - Hydration shell PY - 2023 AN - OPUS4-57646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - BP153: The change of DNA radiation damage upon hydration: In-situ observation by near-ambient pressure XPS N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - DPG Frühjahrstagung CY - Dresden, Germany DA - 26.03.2023 KW - Base damage KW - Base loss KW - Cancer treatment KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break (DSB) KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionization KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Prehydrated electron KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Radiolysis KW - Radiotherapy KW - Reactive oxygen species KW - Simulation KW - Single-strand break (SSB) KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - Particle scattering KW - Presolvated electron KW - ESCA PY - 2023 AN - OPUS4-57255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Near-Ambient-Pressure XPS to investigate radiation damage to DNA N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. T2 - Physical and Chemical Analysis of Polymers seminar CY - Online meeting DA - 12.10.2021 KW - Base damage KW - Base loss KW - Cancer therapy KW - DNA KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Dosimetry KW - Double-strand break KW - DSB KW - Dry DNA KW - Geant4 KW - Geant4-DNA KW - Hydrated DNA KW - Hydrated electron KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionization KW - LEE KW - Low energy electrons KW - Microdosimetry KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - OH radical KW - PES KW - Prehydrated electron KW - Quasi-direct damage KW - ROS KW - Radiation damage KW - Radiation therapy KW - Radical KW - Reactive oxygen species KW - Single-strand break KW - SSB KW - TOPAS KW - TOPAS-nbio KW - XPS KW - Xray KW - Xray photo electron spectrocopy PY - 2021 AN - OPUS4-53611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhattacharya, Biswajit A1 - Michalchuk, Adam A1 - Silbernagl, Dorothee A1 - Rautenberg, Max A1 - Schmid, Thomas A1 - Feiler, Torvid A1 - Reimann, K. A1 - Ghalgaoui, A. A1 - Sturm, Heinz A1 - Paulus, B. A1 - Emmerling, Franziska T1 - A Mechanistic Perspective on Plastically Flexible Coordination Polymers N2 - Mechanical flexibility in single crystals of covalently bound materials is a fascinating and poorly understood phenomenon. We present here the first example of a plastically flexible one-dimensional (1D) coordination polymer. The compound [Zn(m-Cl)2(3,5-dichloropyridine)2]n is flexible over two crystallographic faces. Remarkably, the single crystal remains intact when bent to 1808. A combination of microscopy, diffraction, and spectroscopic studies have been used to probe the structural response of the crystal lattice to mechanical bending. Deformation of the covalent polymer chains does not appear to be responsible for the observed macroscopic bending. Instead, our results suggest that mechanical bending occurs by displacement of the coordination polymer chains. Based on experimental and theoretical evidence, we propose a new model for mechanical flexibility in 1D coordination polymers. Moreover, our calculations propose a cause of the different mechanical properties of this compound and a structurally similar elastic material KW - Coordination polymer KW - Flexible crystals KW - Mechanical properties KW - Plastic deformation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504755 DO - https://doi.org/10.1002/anie.201914798 VL - 59 IS - 14 SP - 5557 EP - 5561 PB - Wiley-VCH AN - OPUS4-50475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wurzler, Nina A1 - Sobol, Oded A1 - Altmann, Korinna A1 - Radnik, Jörg A1 - Özcan Sandikcioglu, Özlem T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part I: Effect on surface chemistry and corrosion behavior N2 - Stainless steel AISI 304 surfaces were studied after a mild anodic polarization for oxide growth in the presence and absence of two derivatives of vitamin B2 (riboflavin and flavin mononucleotide) that can be secreted by metal‐reducing bacteria and act as a chelating agent for iron species. The alterations in oxide chemistry were studied by means of surface‐sensitive techniques such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry analysis. The complementary electrochemical characterization revealed a preferential growth of an oxide/hydroxide iron‐rich film that is responsible for an altered pit initiation and nucleation behavior. These findings suggest that as the corrosion behavior is determined by the interplay of the chemical and electronic properties, only a mild anodic polarization in the presence of redox‐active molecules is able to alter the chemical and electronic structure of the passive film formed on stainless steel AISI 304. This helps to achieve a profound understanding of the mechanisms of microbially influenced corrosion (MIC) and especially the possible effects of the redox‐active biomolecules, as they may play an important role in the corrosion susceptibility of stainless steel surfaces. KW - Corrosion KW - Stainless steel KW - Surface analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528117 DO - https://doi.org/10.1002/maco.202012191 VL - 72 IS - 6 SP - 974 EP - 982 PB - Wiley AN - OPUS4-52811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -