TY - JOUR A1 - Hildebrand, G. A1 - Sänger, Johanna Christiane A1 - Schirmer, U. A1 - Mantei, W. A1 - Dupuis, Y. A1 - Houbertz, R. A1 - Liefeith, K. T1 - Process Development for Additive Manufacturing of Alumina Toughened Zirconia for 3D Structures by Means of Two-Photon Absorption Technique N2 - Additive manufacturing is well established for plastics and metals, and it gets more and more implemented in a variety of industrial processes. Beside these well-established material platforms, additive manufacturing processes are highly interesting for ceramics, especially regarding resource conservation and for the production of complex three-dimensional shapes and structures with specific feature sizes in the µm and mm range with high accuracy. The usage of ceramics in 3D printing is, however, just at the beginning of a technical implementation in a continuously and fast rising field of research and development. The flexible fabrication of highly complex and precise 3D structures by means of light-induced photopolymerization that are difficult to realize using traditional ceramic fabrication methods such as casting and machining is of high importance. Generally, slurry-based ceramic 3D printing technologies involve liquid or semi-liquid polymeric systems dispersed with ceramic particles as feedstock (inks or pastes), depending on the solid loading and viscosity of the system. This paper includes all types of photo-curable polymer-ceramic-mixtures (feedstock), while demonstrating our own work on 3D printed alumina toughened zirconia based ceramic slurries with light induced polymerization on the basis of two-photon absorption (TPA) for the first time. As a proven exemplary on cuboids with varying edge length and double pyramids in the µm-range we state that real 3D micro-stereolithographic fabrication of ceramic products will be generally possible in the near future by means of TPA. This technology enables the fabrication of 3D structures with high accuracy in comparison to ceramic technologies that apply single-photon excitation. In sum, our work is intended to contribute to the fundamental development of this technology for the representation of oxide-ceramic components (proof-of-principle) and helps to exploit the high potential of additive processes in the field of bio-ceramics in the medium to long-term future. KW - Additive manufacturing KW - Ceramics 3D printing KW - Two-photon adsorption KW - Polymer-ceramic mixtures KW - Bio-ceramic engineering PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526672 DO - https://doi.org/10.3390/ceramics4020017 VL - 4 IS - 2 SP - 224 EP - 239 PB - MDPI CY - Basel AN - OPUS4-52667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Omar, Hassan A1 - Smales, Glen Jacob A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Calorimetric and Dielectric Investigations of Epoxy-Based Nanocomposites with Halloysite Nanotubes as Nanofillers N2 - Epoxy nanocomposites are promising materials for industrial applications (i.e., aerospace, marine and automotive industry) due to their extraordinary mechanical and thermal properties. Here, the effect of hollow halloysite nanotubes (HNT) on an epoxy matrix (Ep) was the focus of the study. The structure and molecular mobility of the nanocomposites were investigated using a combination of X-ray scattering, calorimetry (differential (DSC) and fast scanning calorimetry (FSC)) and dielectric spectroscopy. Additionally, the effect of surface modification of HNT (polydopamine (PDA) and Fe(OH)3 nanodots) was considered. For Ep/HNT, the glass transition temperature (Tg) is was de-creased due to a nanoparticle-related decrease of the crosslinking density. For the modified system, Ep/m-HNT, the surface modification resulted in enhanced filler–matrix interactions leading to higher Tg values than the pure epoxy in some cases. For Ep/m-HNT, the amount of interface formed between the nanoparticles and the matrix ranged from 5% to 15%. Through BDS measurements, localized fluctuations were detected as a β- and γ-relaxation, related to rotational fluctuations of phenyl rings and local reorientations of unreacted components. A combination of calorimetry and BDS dielectric spectroscopy revealed a dynamic and structural heterogeneity of the matrix, as confirmed by two glassy dynamics in both systems, related to regions with different crosslinking densities. KW - Rigid amorphous fraction KW - Epoxy nanocomposites KW - Halloysite nanotubes KW - X-ray scattering KW - Differential scanning calorimetry KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526668 DO - https://doi.org/10.3390/polym13101634 VL - 13 IS - 10 SP - 1634 PB - MDPI AN - OPUS4-52666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ciornii, Dmitri A1 - Drobne, D. A1 - Novak, S. A1 - Kranjc, E. A1 - Bohmer, N. A1 - Hodoroaba, Vasile-Dan T1 - Data quality for Nanorisk Governance N2 - Nanomaterials bring various benefits and have become a part of our daily lives. However, the risks emerging from nanotechnology need to be minimized and controlled at the regulatory level and therefore, there is a need for nanorisk governance. One of the prerequisites for successful nanorisk governance is the availability of high-quality data on nanomaterials and their impact with the human body and the environment. In recent decades, a countless number of publications and studies on nanomaterials and their properties have been produced due to the fast development of nanotechnology. Despite such a vast amount of data and information, there are certain knowledge gaps hindering an efficient nanorisk governance process. Knowing the state of the available data and information is an important requirement for any decision maker in dealing with risks. In the specific case of nanotechnology, where most of the risks are complex, ambiguous, and uncertain in nature, it is essential to obtain complete data and metadata, to fill knowledge gaps, and to transform the available knowledge into functional knowledge. This can become possible using a novel approach developed within the NANORIGO project (Grant agreement No. 814530) – the Knowledge Readiness Level (KaRL). In analogy to NASA’s Technology Readiness Levels (TRLs), we define KaRLs as a categorization system of data, information, and knowledge which enables transformation of data and information into functional knowledge for nanorisk governance. Our approach goes beyond the technical curation of data and metadata and involves quality and completeness filters, regulatory compliance requirements, nanorisk-related tools, and most importantly, human input (inclusion of all stakeholder groups). With the KaRL approach we also address key issues in nanotechnology such as societal and ethical concerns, circular economies and sustainability, the Green Deal, and the traceability of data, knowledge, and decisions. The KaRL approach could be used for nanorisk governance by a nanorisk governance council (NRGC), which is currently under development by three EU projects (NANORIGO, GOV4NANO, and RISKGONE). T2 - Nanosafety Training School: From Basic Science To Risk Governance CY - Online meeting DA - 20.06.2021 KW - Data KW - Knowledge KW - Risk Governance KW - Knowledge Readiness Level PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529255 AN - OPUS4-52925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mezera, Marek A1 - Mirabella, Francesca A1 - Wasmuth, Karsten A1 - Richter, Anja A1 - Schwibbert, Karin A1 - Bennet, Francesca A1 - Krüger, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Influence of the pulse repetition rate on the chemical and morphological properties of laser generated surface structures N2 - Inter-pulse accumulation of heat could affect the chemical and morphological properties of the laser processed material surface. Hence, the laser pulse repetition rate may restrict the processing parameters for specific laser-induced surface structures. In this study, the evolution of various types of laser-induced micro- and nanostructures at various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz) are studied for common metals/alloys (e.g. steel or titanium alloy) irradiated by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment. The processed surfaces were characterized by optical and scanning electron microscopy (OM, SEM), energy dispersive X-ray spectroscopy (EDX) as well as time of flight secondary ion mass spectrometry (TOF-SIMS). The results show that not only the surface morphology could change at different laser pulse repetition rates and comparable laser fluence levels and effective number of pulses, but also the surface chemistry is altered. Consequences for medical applications are outlined. T2 - European Materials Research Society Spring 2021 Meeting CY - Online meeting DA - 31.05.2021 KW - Laser-induced pariodic surface structures KW - LIPSS PY - 2021 AN - OPUS4-52778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ciornii, Dmitri A1 - Drobne, D. A1 - Novak, S. A1 - Kranjc, E. A1 - Bohmer, N. A1 - Hodoroaba, Vasile-Dan T1 - Knowledge Readiness for Nanorisk Governance N2 - Nanomaterials bring various benefits and have become a part of our daily lives. However, the risks emerging from nanotechnology need to be minimized and controlled at the regulatory level and therefore, there is a need for nanorisk governance. One of the prerequisites for successful nanorisk governance is the availability of high-quality data on nanomaterials and their impact with the human body and the environment. In recent decades, a countless number of publications and studies on nanomaterials and their properties have been produced due to the fast development of nanotechnology. Despite such a vast amount of data and information, there are certain knowledge gaps hindering an efficient nanorisk governance process. Knowing the state of the available data and information is an important requirement for any decision maker in dealing with risks. In the specific case of nanotechnology, where most of the risks are complex, ambiguous, and uncertain in nature, it is essential to obtain complete data and metadata, to fill knowledge gaps, and to transform the available knowledge into functional knowledge. This can become possible using a novel approach developed within the NANORIGO project (Grant agreement No. 814530) – the Knowledge Readiness Level (KaRL). In analogy to NASA’s Technology Readiness Levels (TRLs), we define KaRLs as a categorization system of data, information, and knowledge which enables transformation of data and information into functional knowledge for nanorisk governance. Our approach goes beyond the technical curation of data and metadata and involves quality and completeness filters, regulatory compliance requirements, nanorisk-related tools, and most importantly, human input (inclusion of all stakeholder groups). With the KaRL approach we also address key issues in nanotechnology such as societal and ethical concerns, circular economies and sustainability, the Green Deal, and the traceability of data, knowledge, and decisions. The KaRL approach could be used for nanorisk governance by a nanorisk governance council (NRGC), which is currently under development by three EU projects (NANORIGO, GOV4NANO, and RISKGONE). T2 - Gov4Nano: data management core group CY - Online meeting DA - 05.07.2021 KW - Data Management KW - Knowledge Readiness Level KW - Nanorisk Governance KW - Participatory Approach KW - Sustainability PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529264 AN - OPUS4-52926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reichelt, Manuel A1 - Cappella, Brunero T1 - Micro- and nanowear of self-mated steel generated and studied with an AFM at the single asperity level N2 - We show for the first time tribotests performed with self-mated 100Cr6 steel, taking advantage of an AFM, employed as a tribometer for the tribotests as well as for the inspection of wear of both tribopartners. Emphasis is put on the morphology of the scars, on wear particles, and on wear of the “colloidal” particles glued on the AFM cantilever. Measurements demonstrate the possibility of characterizing single asperity events leading to very small wear. We highlight several phenomena, which are elementary key constituents of tribological processes. Such phenomena, probably occurring also at the macroscale, can be detected, identified, and characterized with high spatial and time resolution only at the nanoscale, thus giving insight into conditions and causes of their emergence. KW - Nanowear KW - Atomic force microscope KW - 100Cr6 (AISI 52100) steel KW - Wear particles KW - Single asperity contact KW - Particle transfer KW - Zero wear PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531389 DO - https://doi.org/10.3389/fmech.2021.722434 SN - 2297-3079 VL - 7 SP - 1 EP - 16 PB - Frontiers Media CY - Lausanne AN - OPUS4-53138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Fischer, Daniel A1 - Freiberg, K. A1 - Duwe, M. A1 - Sahre, Mario A1 - Schneider, S. A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Rettenmayr, M. A1 - Beck, Uwe A1 - Undisz, A. A1 - Bonse, Jörn T1 - Silicon surface amorphization and re-crystallization via single femtosecond laser pulses N2 - Silicon is the material responsible for most of the technological developments during the past century, making it one of the most studied materials along different disciplines. However, there are still unturned stones regarding its superficial re-solidification after femtosecond laser-induced local melting. In this presentation, we report irradiation experiments with single femtosecond pulses (790 nm, 30 fs) with a spatially Gaussian distribution on two different types of silicon with orientations <111> and <100>. The surface modifications were studied in detail via different techniques, including optical microscopy, atomic force microscopy, spectroscopic imaging ellipsometry, energy dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. We quantitatively estimate the resulting radial amorphous layer depth profiles with maximum thicknesses around some tenths of nanometers for fluences in between the melting and ablation thresholds. In particular, spectroscopic imaging ellipsometry (SIE) allowed fast data acquisition using multiple wavelengths to provide experimental measurements for calculating the nanometric radial amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. SIE proved to be capable of detecting and measuring nanometric structural and chemical modifications (oxidation) on the studied laser spots. The accuracy of the SIE-based calculations is verified experimentally by characterizing an in-depth material lamella via high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). For completeness, we present a mathematical modelling for the melt layer thickness considering different optical absorption processes including one photon absorption, two photon absorption and free-carrier absorption, highlighting the relevance of the latter one in the femtosecond laser-induced melting of silicon. T2 - 28th International Conference on Advanced Laser Technologies (ALT'21) CY - Online meeting DA - 06.09.2021 KW - Silicon KW - Femtosecond laser KW - Phase transitions KW - Spectroscopic imaging ellipsometry KW - Transmission electron microscopy PY - 2021 AN - OPUS4-53235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - VAMAS TWA 37 - Quantitative Microstructural Analysis & Liaison with ISO/TC 202 Microbeam Analysis, Liaison with ISO N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 46th Steering Committee Meeting CY - Online meeting DA - 08.09.2021 KW - VAMAS KW - Nanoparticles KW - Standardisation KW - Inter-laboratory comparison KW - ISO/TC 202 KW - ISO/TC 229 KW - ISO/TC 201 KW - Microstructure KW - EBSD PY - 2021 UR - http://www.vamas.org/twa/ AN - OPUS4-53237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Anja A1 - Mezera, Marek A1 - Buchberger, G. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Heitz, J. A1 - Schwibbert, Karin T1 - Laser-processing – a tool to direct biofilm formation N2 - Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms, often with enhanced resistance towards antimicrobial treatment and established cleaning procedures. On e.g. medical implants, in water supply networks or food-processing industry, biofilms can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. Nowadays, the emergence of resistances because of extensive usage of antibiotics and biocides in medicine, agriculture and private households have become one of the most important medical challenges with considerable economic consequences. In addition, aggravated biofilm eradication and prolonged cell-surface interaction can lead to increased biodeterioration and undesired modification of industrial and medical surface materials. Various strategies are currently developed, tested, and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics. In this study, contact-less and aseptic large-area short or ultrashort laser processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials such as titanium-alloy and polyethylene terephthalate (PET). The laser processed surfaces were subjected to bacterial colonization studies with Escherichia coli test strains and analyzed with reflected-light and epi-fluorescence microscopy. Depending on the investigated surfaces, different bacterial adhesion patterns were found, ranging from bacterial-repellent to bacterial-attractant effects. The results suggest an influence of size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself, emphasizing the potential of laser-processing as a versatile tool to control bacterial surface adhesion. T2 - International Biodeterioration & Biodegradation Symposium 2021 CY - Online meeting DA - 06.09.2021 KW - Bacterial adhesion KW - Biofilm formation KW - Laser-induced periodic surface structueres (LIPPS) KW - Laser processing PY - 2021 UR - https://www.ibbs18.org/programme AN - OPUS4-53223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fiedler, Saskia A1 - Mortensen, N. A. A1 - Wolff, C. A1 - Morozov, S. A1 - Illiushyn, L. A1 - Booth, T. J. A1 - Stenger, N. A1 - Tserkezis, C. T1 - Giant photon bunching of WS2 monolayer in cathodoluminescence N2 - Cathodoluminescence (CL) spectroscopy has become a powerful tool to study nanostructures due to its high spectral and spatial resolution down to sub-nanometer. More recently, CL technique has also been used for second order auto-correlation measurements (g(2)(t)) to identify different single photon emitters and photon bunching in different materials [1-2]. In this work, tungsten disulfide (WS2) monolayers encapsulated in hexagonal boron nitride (hBN) with and without monocrystalline Au nanodisks (NDs) have been studied, using CL and PL spectroscopy as well as g(2)-CL- and PL-measurements. CL and PL maps of different WS2 monolayers before/after Au ND deposition show a narrow peak at ~625 nm without any background emission. In CL, the hBN not only protects WS2 from the electron beam but also acts as a charge carrier sink which substantially increases the CL signal [3]. A further CL enhancement is achieved by Au ND deposition, exhibiting the maximum at the center of the NDs without any size dependence. The PL intensity is unaffected. This indicates that Purcell enhancement cannot be the underlying mechanism. Furthermore, a giant CL-photon bunching of the hBN-encapsulated WS2 monolayers is found which is independent of the applied voltage but highly dependent on the electron beam current. At the lowest current of ~2 pA, a CL bunching factor of up to 160 is observed. Varying thicknesses of the surrounding hBN increases the overall CL signal but does not affect the bunching factor, though it exhibits small local changes within the same flake. In contrast, there is no PL correlation (g(2)(0) = 1). Interestingly, this photon bunching can be further increased by Au NDs, resulting in the highest ever observed bunching factor of close to 2200. Once again, this enhancement is independent of the Au ND’s diameter although some disks show higher bunching factors than others. Most likely, the Au acts as shield for the incoming primary electrons, resulting in an even further decreased current, and thereby, increased bunching. In conclusion, large CL-photon bunching is found in hBN-encapsulated WS2 monolayers which can be substantially enhanced by Au NDs. References [1] M.A. Feldmann, E.F. Demitrescu, D. Bridges, M.F. Chisholm, R.B. Davidson, P.G. Evans, J.A. Hachtel, A. Hu, R.C. Pooser, R.F. Haglund, B.J. Lawrie, Phys. Rev. B, 97, 081404(R) (2018) [2] S. Meuret, L.H.G. Tizei, T. Cazimajou, R. Bourrellier, H.C. Chang, F. Treussartm M. Kociak, Phys. Rev. Letter, 114, 197401 (2015) [3] S. Zheng, J.-K. So, F. Liu, Z. Liu, N. Zheludev, H.J. Fan, Nano Lett., 17, 6475-6480 (2017) T2 - GSELOP2021 CY - Paris, France DA - 23.08.2021 KW - Cathodoluminescence KW - Photon bunching KW - 2D materials KW - TMDCs KW - Au nanodisks KW - Transition metal dichalcogenide KW - Au nanoparticles PY - 2021 AN - OPUS4-53153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Prinz, Carsten A1 - Rühle, Bastian A1 - Haase, Oskar A1 - Kuchenbecker, Petra A1 - Löhmann, Oliver A1 - Hodoroaba, Vasile-Dan A1 - Bresch, Harald A1 - Resch-Genger, Ute T1 - Iron oxide nanoparticles as a reference material candidate for particle size measurements N2 - This poster presentation covers the development of iron oxide nanoparticles as reference material candidate in the context of the project "Nanoplattform". T2 - EMRS Spring Meeting CY - Online meeting DA - 31.05.2021 KW - Iron oxide nanoparticles KW - Reference material KW - Particle size KW - Transmission electron microscopy KW - Small angle x-ray scattering PY - 2021 AN - OPUS4-52773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Prinz, Carsten A1 - Rühle, Bastian A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Monodisperse iron oxide nanoparticles as reference material candidate for particle size measurements N2 - In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. Furthermore, the European Commission’s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution and will also target other key parameters like shape, structure, porosity or functional properties. In this respect, materials like iron oxide or titanium dioxide are considered as candidates to complement the already available silica, Au, Ag, and polystyrene reference nanoparticles. The thermal decomposition of iron oleate precursors in high boiling organic solvents can provide large quantities of iron oxide nanoparticles that can be varied in size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. Such monodisperse, spherical particles were synthesized at BAM and pre-characterized by electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM) and dynamic light scattering comparing cumulants analysis and frequency power spectrum. 1. REACH regulations and nanosafety concerns create a strong need for nano reference materials with diverse properties. 2. Iron oxide nanoparticles are under development as new candidate reference material at BAM. 3. Narrow particle size distribution confirmed by light scattering and electron microscopy. T2 - Nanosafety 2020 CY - Online meeting DA - 05.10.2020 KW - Iron oxide nanoparticles KW - Reference material KW - Particle size KW - Electron microscopy KW - Nanoplattform PY - 2020 AN - OPUS4-52774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Schönhals, Andreas T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy-based Materials N2 - This work deals with an in-depth comparative investigation of the structure, molecular mobility and vitrification kinetics of three bisphenol A diglycidyl ether (DGEBA)-based materials with different nanofillers: taurine-modified layered double hydroxide (T-LDH) and halloysite nanotubes (HNTs). The chosen methodology comprises I) small – and wide – angle X-ray scattering (SAXS/WAXS) II) calorimetry in the forms of a) conventional DSC and b) static fast scanning calorimetry (FSC), III) broadband dielectric spectroscopy (BDS), as well as IV) specific heat spectroscopy in the forms of a) temperature modulated DSC, and b) temperature modulated FSC. T2 - Abteilungsseminar 6. - FB 6.6 CY - Online meeting DA - 06.05.2021 KW - Broadband dielectric spectroscopy KW - Epoxy nanocomposites KW - Halloysite nanotubes KW - X-ray scattering KW - Differential scanning calorimetry KW - Rigid amorphous fraction KW - Flash DSC PY - 2021 AN - OPUS4-52697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Déziel, J.-L. A1 - Kirner, Sabrina V. A1 - Siegel, J. A1 - Bonse, Jörn T1 - Femtosecond laser-induced oxidation in the formation of periodic surface structures N2 - Laser-induced oxide graded layers may contribute to the formation of a new type of embedded low-spatial frequency LIPSS with an anomalous orientation parallel to the laser polarization. In this contribution, we explore this effect experimentally with femtosecond laser pulses and numerically by finite-difference time-domain (FDTD) calculations. T2 - 2021 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Virtual Conferences CY - Online meeting DA - 21.06.2021 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface oxidation KW - Femtosecond laser ablation KW - Finite-difference time-domain calculations PY - 2021 AN - OPUS4-52859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Burr, L. A1 - Schmid, D. A1 - Hodoroaba, Vasile-Dan T1 - Towards a method for quantitative evaluation of nanoparticle from suspensions via microarray printing and SEM analysis N2 - As part of the development of a library of accurate and efficient methods for measurement of nanoparticle properties, we develop and optimize a method for the efficient analysis of nanoparticle size distribution from suspensions via microprinting and digital analysis of electron microscopy (SEM and TEM) images, with the ultimate aim of automated quantitative concentration analysis (calculated from drop volume). A series of different nanoparticle suspensions (gold, latex, and SiO2 in varying sizes and concentrations) were printed onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 nanoparticles/mL and imaged with SEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee-ring effect. KW - Nanoparticles KW - Particle size distribution KW - Electron microscopy KW - Microarray printing KW - Sample preparation KW - Nanoparticle concentration PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528455 DO - https://doi.org/10.1088/1742-6596/1953/1/012002 VL - 1953 SP - 012002 PB - IOP Publishing AN - OPUS4-52845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hodoroaba, Vasile-Dan T1 - BAM reference data - EDS raw data of Al-coated titania nanoparticles (JRCNM62001a and JRCNM62002a) N2 - EDS spectra of Al-coated titania nanoparticles (JRCNM62001 and JRCNM62002a) provided by the JRC repository are provided. KW - EDS KW - Titania nanoparticles KW - BAM reference data PY - 2021 DO - https://doi.org/10.5281/zenodo.4986420 PB - Zenodo CY - Geneva AN - OPUS4-52833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bennet, Francesca A1 - Hodoroaba, Vasile-Dan T1 - BAM reference data - SEM raw data for the particles size distribution of Al-coated titania nanoparticles (JRCNM62001a and JRCNM62002a) N2 - SEM raw images of Al-coated titania nanoparticles (JRCNM62001 and JRCNM62002a) provided by the JRC repository are provided together with the particle size distribution of the minimum Feret Diameter extracted from the given images. KW - SEM KW - Titania nanoparticles KW - Particle size distribution KW - BAM reference data PY - 2021 DO - https://doi.org/10.5281/zenodo.5007367 PB - Zenodo CY - Geneva AN - OPUS4-52836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Wonneberger, R. A1 - Undisz, A. A1 - Kirner, Sabrina V. A1 - Wasmuth, Karsten A1 - Spaltmann, Dirk A1 - Krüger, Jörg T1 - Surface oxidation accompanying the formation of various types of femtosecond laser-generated surface structures on titanium alloy N2 - Different types of laser-generated surface structures, i.e., Laser-induced Periodic Surface Structures (LIPSS, ripples), Grooves, and Spikes are generated on titanium and Ti6Al4V surfaces by means of femtosecond (fs) laser scan processing (790 nm, 30 fs, 1 kHz) in ambient air. Morphological, chemical and structural properties of the different surface structures are characterized by various surface analytical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Glow discharge optical emission spectroscopy (GD-OES), and depth-profiling Auger electron spectroscopy (AES). It is revealed that the formation of near-wavelength sized LIPSS is accompanied by the formation of a graded oxide extending several tens to a few hundreds of nanometers into depth. GD-OES performed on other superficial fs-laser generated structures produced at higher fluences and effective number of pulses per spot area such as periodic Grooves and irregular Spikes indicate even thicker graded oxide layers. These graded layers may be suitable for applications in prosthetics or tribology. T2 - E-MRS Spring Meeting 2021 CY - Online meeting DA - 31.05.2021 KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium alloy KW - Oxidation KW - Glow-discharge optical emission spectroscopy PY - 2021 AN - OPUS4-52749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Rudenko, A. A1 - Déziel, J.-L. A1 - Florian, Camilo A1 - Krüger, Jörg A1 - Siegel, J. A1 - Colombier, J.-P. T1 - The role of electromagnetic scattering in the formation of laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon that is accompanying laser materials processing. These surface nanostructures pave a simple way for surface functionalization with numerous applications in optics, fluidics, tribology, medicine, etc. During the last decade remarkable experimental and theoretical improvements in understanding of their formation mechanisms were obtained - all pointing toward polarization-dependent energy deposition by absorption of optical radiation that is scattered at the surface roughness and interfering with the laser beam. This contribution reviews the current state-of-the-art on the role of electromagnetic scattering in the formation of LIPSS by ultrashort laser pulses. Special attention is drawn to recent finite-difference time-domain (FDTD) calculations that allow to visualize the radiation patterns formed in the vicinity of the sample surface and to the impact of a thin superficial laser-induced oxidation layer. T2 - E-MRS Spring Meeting 2021 CY - Online meeting DA - 31.05.2021 KW - Laser-induced periodic surface structures (LIPSS) KW - Optical scattering KW - Oxidation KW - Femtosecond laser PY - 2021 AN - OPUS4-52729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Angurel, L.A. A1 - Cubero, A. A1 - Martínez, E. A1 - de la Fuente, G.F. A1 - Navarro, R. A1 - Legall, Herbert A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Effects of laser surface processing under different atmospheres on the superconducting properties of pure niobium N2 - Niobium metal is the pure element with the highest superconducting critical temperature (T_c = 9.2 K), which is present in many applications. Particularly, in superconducting radio frequency (SRF) cavities of particle accelerators, the control of the surface characteristics of pure Nb is crucial, as the presence of defects may generate magnetic flux pinning that can increase by more than two orders of magnitude the surface critical current, ic. Several procedures such as chemical- or electro-polishing have been used aiming at cleaning surface contamination and decreasing its roughness. Sub-nanosecond lasers can be applied to generate a broad range of micro and nanostructures (e.g. Laser-Induced Periodic Surface Structures, LIPSS) that strongly modify the materials properties - as wettability, color, oxidation resistance or antibacterial behavior. In this work, we analyze a variety of surface structures generated on pure Nb sheets with different laser systems (UV, Vis and n-IR, fs and ps) by exploring a range of processing parameters. These include pulse overlap, irradiance or the effective number of pulses, under different atmospheres (air, N2, Ar, vacuum). The effects on Tc, critical currents and critical fields (Bc1, Bc2 and Bc3) have been obtained from magnetization, ac susceptibility and heat capacity measurements, revealing their dependence with the different surface nanostructures and the chemical changes generated with these laser treatments. T2 - E-MRS Spring Meeting 2021 CY - Online meeting DA - 31.05.2021 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Niobium KW - Superconductivity PY - 2021 AN - OPUS4-52730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Keshmiri, Hamid A1 - Armin, F. A1 - Elsayad, K. A1 - Schreiber, Frank A1 - Moreno, M. T1 - Leaky and waveguide modes in biperiodic holograms N2 - This study details a theoretical analysis of leaky and waveguide modes in biperiodic all-dielectric holograms. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a new class of highly sensitive refractive index biosensing platforms that are capable of resolving 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes. KW - Antimicrobial resistance KW - Bacteria KW - Photonics KW - Diffractive gratings PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527632 DO - https://doi.org/10.1038/s41598-021-89971-1 SN - 2045-2322 (online) VL - 11 IS - 1 SP - 10991 PB - Springer Nature AN - OPUS4-52763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Hörenz, Christoph A1 - Mansfeld, Ulrich A1 - Pellegrino, F. A1 - Maurino, V. A1 - Marguet, S. A1 - Testard, F. A1 - Taché, O. A1 - Bartczak, D. A1 - Nunez, S. A1 - Abad Alvaro, I. A1 - Goenaga-Infante, H. T1 - Other than spherical/monodisperse Towards real world NPs as candidate reference materials for traceable size measurements N2 - By far most of the current nanoparticle (NP) research is dealing with (quasi-) spherical and/or monodisperse particles. However, many NPs used in industrial applications are rather aspherical and polydisperse. This inhomogeneity considerably hampers their characterization and, particularly, the accurate determination of the nanoparticle size. In order to overcome this problem and to promote the availability of standardized size measurement methods, it is crucial to develop and establish (candidate) reference materials with inhomogeneous size (distribution), aspherical shape as well as agglomerated or aggregated particles. Therefore, a new set of NPs including Au-, SiO2 , and TiO2-particles is investigated. The range of properties comprises polydisperse spherical, bimodal spherical, rod-like, acicular, bipyramidal, sheet-like as well as cubic NPs. With respect to a good traceability of the measurements, size and size distributions of the candidate reference materials are determined using microscopic methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning electron microscopy in transmission mode (STEM-in-SEM), atomic force microscopy (AFM) as well as small angle X-ray scattering (SAXS) as an ensemble technique. The development of protocols for sample preparation is of particular importance to obtain a homogeneous dispersion of the NPs on a substrate. Further, approaches for signal modelling for all the methods above are being developed. The initiation of two VAMAS (www.vamas.org/twa34/index.html) inter-laboratory comparisons on bipyramidal titania and bimodal silica with different modal concentration ratios will be also highlighted. T2 - E-MRS Spring Meeting 2021 CY - Online meeting DA - 31.05.2021 KW - Nanoparticles KW - Particle size distribution KW - Imaging KW - Traceability KW - Reference material PY - 2021 AN - OPUS4-52764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Anja A1 - Mezera, Marek A1 - Thiele, Dorothea A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Schwibbert, Karin T1 - Bacterial adhesion on ultrashort laser processed surfaces N2 - Bacterial biofilms are multicellular communities adhering to surfaces and embedded in a self-produced extracellular matrix. Due to physiological adaptations and the protective biofilm matrix itself, biofilm cells show enhanced resistance towards antimicrobial treatment. In medical and industrial settings, biofilms on e.g. for implants or for surfaces in food-processing industry can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. As extensive usage of antibiotics and biocides can lead to the emergence of resistances, various strategies are currently developed, tested and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics. In this study, contact-less and aseptic large-area ultrashort laser scan processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials, i.e. titanium-alloy, steel, and polymer. The processed surfaces were characterized by optical and scanning electron microscopy and subjected to bacterial colonization studies with Escherichia coli test strains. For each material, biofilm results of the fs-laser treated surfaces are compared to that obtained on polished (non-irradiated) surfaces as a reference. Depending on the investigated surfaces, different bacterial adhesion patterns were found, suggesting an influence of geometrical size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself. T2 - European Materials Research Society Spring Meeting 2021 CY - Online Meeting DA - 31.05.2021 KW - Bacterial adhesion KW - Biofilm formation KW - Ultrashort laser processing KW - Laser-induced periodic surface structures (LIPSS) PY - 2021 UR - https://www.european-mrs.com/laser-material-processing-fundamental-interactions-innovative-applications-emrs AN - OPUS4-52765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Mezera, Marek A1 - Florian, Camilo A1 - Krüger, Jörg A1 - Gräf, S. T1 - Laser-induced periodic surface structures: When electromagnetics drives hydrodynamics N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any material upon irradiation of solids with intense laser radiation. Nowadays processing rates of up to m^2/min are enabling new industrial applications in medicine, optics, tribology, biology, etc. Depending on the specific type of LIPSS, their structural sizes typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, however, a vivid, controversial, and long-lasting debate has emerged during the last two decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter reorganization processes (distinctly after the laser irradiation). This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches. T2 - 28th International Conference on Advanced Laser Technologies (ALT'21) CY - Online meeting DA - 06.09.2021 KW - Laser-induced periodic surface structures, LIPSS KW - Electromagnetic scattering KW - Matter reorganization PY - 2021 DO - https://doi.org/10.24412/cl-35039-2021-21-25-25 AN - OPUS4-53218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mirabella, Francesca A1 - Mezera, Marek A1 - Wasmuth, Karsten A1 - Hertwig, Andreas A1 - Richter, Anja A1 - Schwibbert, Karin A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Hodoroaba, Vasile-Dan T1 - ToF-SIMS as a new tool for nano-scale investigation of ps-laser-generated surface structures on titanium substrates N2 - In recent years, the fabrication of laser-generated surface structures on metals such as titanium surfaces have gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces. The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, laser light polarization type and direction, angle of incidence, and the effective number of laser pulses per beam spot area. However, the characterization of the different surface structures can be difficult because of constraints regarding the analytical information from both depth and the topographic artifacts which may limit the lateral and depth resolution of elemental distributions as well as their proper quantification. A promising technique to investigate these structures even at the nano-scale is Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), a very surface sensitive technique that at the same time allows to perform depth-profiling, imaging and 3D-reconstruction of selected ion-sputter fragment distributions on the surface. In this study we combine chemical analyses such as Energy Dispersive X-ray spectroscopy (EDX) and high-resolution scanning electron microscopy (SEM) analyses with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti and Ti alloys at different laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz), following irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment or under argon gas flow. We show how this combined surface analytical approach allows to evaluate alteration in the surface chemistry of the laser-generated surface structures depending on the laser processing parameters and the ambient environment. T2 - European Materials Research Society (EMRS) Fall Meeting 2021 CY - Online meeting DA - 20.09.2021 KW - ToF SIMS KW - Nano characterization PY - 2021 AN - OPUS4-53366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Feltin, N. A1 - Crouzier, L. A1 - Cios, G. A1 - Tokarski, T. T1 - Correlative imaging analysis of non-spherical nanoparticles N2 - It sounds like being a simple analytical task, it is definitely not. The way toward accurate measurement of the size distribution of nanoparticles (NPs) with complex shape, having a broad size polydispersity, with inhomogeneous chemistry, and with a high degree of agglomeration/aggregation is very challenging for all available analytical methods. Particularly for the NPs with complex shape, the access to the smallest dimension (as e.g. required for regulatory purposes) can be enabled only by using imaging techniques with spatial resolution at the nanoscale. Moreover, the full 3D-chacterisation of the NP shape can be provided either by advanced characterization techniques like 3D-TEM tomography or by correlative analysis, i. e. synergetic/complementary measurement of the same field-of-view of the sample with different probes. Examples of the latter type of analysis are: i) electron microscopy for the lateral dimensions and AFM for the height of the NPs, ii) SEM with STEM-in-SEM (also called T-SEM), iii) Electron Microscopy with TKD (Transmission Kikuchi Diffraction) for determination of the geometrical orientation of crystalline NPs, iv) Raman and SEM for e.g. thickness of graphen flakes, or v) Electron Microscopy for descriptive NP shape and SAXS for the NP concentration, the latter as a NP property able to be measured with higher and higher accuracy. For all these types of measurement, reference NPs are necessary for the validation of the measured size. Particularly non-spherical reference NPs are still missing. Examples of such new reference NPs as characterized by the correlative analyses enumerated above will be presented in detail in the contribution. T2 - 2021 Fall Meeting of the European Materials Research Society (E-MRS) CY - Online meeting DA - 20.9.2021 KW - Nanoparticles KW - Transmission Kikuchi Diffraction (TKD) KW - Correlative imaging KW - Electron microscopy KW - AFM KW - TiO2 KW - VAMAS PY - 2021 UR - https://www.european-mrs.com/meetings/2021-fall-meeting AN - OPUS4-53367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas T1 - Phase Behaviour and Molecular Mobility of a confined Ionic Liquid Crystal N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing orientational order and phase transition behaviors. Here, the plastic crystal to hexagonal columnar, and hexagonal columnar to isotropic transition temperatures are studied for the guanidinium-based ionic discotic liquid crystal confined in self- ordered nanoporous alumina membranes. The phase transition temperature of the plastic crystal to hexagonal columnar phase is reduced with inverse pore diameter. The hexagonal columnar to isotropic transition is suppressed completely in all pores and a possible explanation is given. The results are of technological relevance for the design of liquid crystal-based devices such as batteries and sensors with optimum tunable properties. T2 - Interpore Konferenz CY - Online meeting DA - 31.05.2021 KW - Ionic Liquid crystals KW - Nanoconfinement KW - Conductivity PY - 2021 AN - OPUS4-53298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Böhning, Martin T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation N2 - We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all Poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model. T2 - IDS Online conference 2021 CY - Online meeting DA - 06.09.2021 KW - Glass transition KW - Conductivity KW - Dynamics KW - Fast Scanning Calorimetry PY - 2021 AN - OPUS4-53299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan A1 - Rabe, Torsten T1 - Comparative study of suitable preparation methods to evaluate irregular shaped, polydisperse nanoparticles by scanning electron microscopy (SEM). N2 - Reliable characterization of materials at the nanoscale regarding their physio-chemical properties is a challenging task, which is important when utilizing and designing nanoscale materials. Nanoscale materials pose a potential toxicological hazard to the environment and the human body. For this reason, the European Commission amended the REACH Regulation in 2018 to govern the classification of nanomaterials, relying on number-based distribution of the particle size. Suitable methods exist for the granulometric characterization of monodisperse and ideally shaped nanoparticles. However, the evaluation of commercially available nanoscale powders is problematic. These powders tend to agglomerate, show a wide particle size distribution and are of irregular particle shape. Zinc oxide, aluminum oxide and cerium oxide with particle sizes less than 100 nm were selected for the studies and different preparation methods were used comparatively. First, the nanoparticles were dispersed in different dispersants and prepared on TEM-supported copper grids. Furthermore, individual powders were deposited on carbon-based self-adhesive pads. In addition, the samples were embedded by hot mounting and then ground and polished. The prepared samples were investigated by scanning electron microscopy (including the transmission mode STEM-in-SEM) and Dynamic Light scattering. The software package ImageJ was used to segment the SEM images and obtain the particle sizes and shapes and finally the number-based particles size distribution with size expressed as various descriptors. T2 - Ceramics 2021 CY - Online meeting DA - 19.04.2021 KW - Nanoparticles KW - Preparation KW - Characterization PY - 2021 AN - OPUS4-53272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob T1 - The Meticulous Approach: Fully traceable X-ray scattering data via a comprehensive lab methodology N2 - To find out if experimental findings are real, you need to be able to repeat them. For a long time, however, papers and datasets could not necessarily include sufficient details to accurately repeat experiments, leading to a reproducibility crisis. It is here, that the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration) tries to implement change – at least for small- and wide-angle X-ray scattering (SAXS/WAXS). In the MOUSE project, we have combined: a) a comprehensive laboratory workflow with b) a heavily modified, highly automated Xenocs Xeuss 2.0 instrumental component. This combination allows us to collect fully traceable scattering data, with a well-documented data flow (akin to what is found at the more automated beamlines). With two full-time researchers, the lab collects and interprets thousands of datasets, on hundreds of samples for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data. While these numbers do not light a candle to those achieved by our hardworking compatriots at the synchrotron beamlines, the laboratory approach does allow us to continually modify and fine-tune the integral methodology. So for the last three years, we have incorporated e.g. FAIR principles, traceability, automated processing, data curation strategies, as well as a host of good scattering practices into the MOUSE system. We have concomitantly expanded our purview as specialists to include an increased responsibility for the entire scattering aspect of the resultant publications, to ensure full exploitation of the data quality, whilst avoiding common pitfalls. This talk will discuss the MOUSE project1 as implemented to date, and will introduce foreseeable upgrades and changes. These upgrades include better pre-experiment sample scattering predictions to filter projects on the basis of their suitability, exploitation of the measurement database for detecting long-term changes and automated flagging of datasets, and enhancing MC fitting with sample scattering simulations for better matching of odd-shaped scatterers. T2 - S4SAS CY - Online meeting DA - 01.09.2021 KW - X-ray scattering KW - Methodology KW - MOUSE KW - Data organization KW - Automation KW - Traceability PY - 2021 AN - OPUS4-53273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Sebastian A1 - Cappella, Brunero T1 - Friction and mechanical properties of AFM-scan-induced ripples in polymer films N2 - In the present paper, friction and mechanical properties of AFM-Scan-Induced ripple structures on films of polystyrene and poly-n-(butyl methacrylate) are investigated. Force volume measurements allow a quantitative analysis of the elastic moduli with nanometer resolution, showing a contrast in mechanical response between bundles and troughs. Additionally, analysis of the lateral cantilever deflection shows a clear correlation between friction and the sample topography. Those results support the theory of crack propagation and the formation of voids as a mechanism responsible for the formation of ripples. This paper also shows the limits of the presented measuring methods for soft, compliant, and small structures. KW - AFM KW - Polymer KW - Ripples KW - Mechanical properties KW - Friction PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532772 DO - https://doi.org/10.3389/fmech.2021.672898 SN - 2297-3079 VL - 7 SP - 1 EP - 8 PB - Frontiers Media CY - Lausanne AN - OPUS4-53277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chudoba, T. A1 - Schwenk, D. A1 - Reinstädt, P. A1 - Griepentrog, Michael T1 - High-Precision Calibration of Indenter Area Function and Instrument Compliance N2 - The accuracy and comparability of nanoindentation results depend significantly on the calibration of area function and instrument compliance. The area function results should not depend on the reference material used or on the calibration method (direct or indirect). This has been investigated for 18 different Berkovich tips. A novel calibration method is proposed that confirms the material independence of the area function and gives a force-dependent instrument compliance function. An agreement between direct and indirect calibration could only be achieved by considering a radial displacement correction. Further, it is shown that the transition range from a spherical cap to the correct face angle of the pyramid can extend to a depth of more than 250 nm. A better parameter for the indenter than the tip radius is the offset of the contact radius to the radius of an ideal tip at a depth where the correct face angle is reached. KW - Nanoindentation KW - Calibration KW - Indenter area function KW - Instrument compliance PY - 2022 DO - https://doi.org/10.1007/s11837-022-05291-3 SN - 1047-4838 VL - 74 IS - 6 SP - 2179 EP - 2194 PB - Springer AN - OPUS4-55849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Surface nanotexturing by ultrashort laser pulses N2 - The presentation reviews the BAM activities in the field of surface processing by ultrashort laser pulses. A focus is laid on the generation of laser-induced periodic surface structures (LIPSS) which allow various surface functionalizations for applications in optics, tribology, liquid management, and medicine. T2 - Photonics Days Berlin Brandenburg 2022 CY - Berlin, Germany DA - 05.10.2022 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Surface functionalization PY - 2022 AN - OPUS4-55921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas T1 - Side Chain length dependent dynamics and conductivity of self assembled ion channels 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 and the αcore process, that correspond to the localized relaxation of the alkyl chains, and cooperative motions of the aromatic core in the columns respectively. Both the relaxation and the αcore process slow down with increasing alkyl chain length. SHS reveals one relaxation process, the αalkyl process that has similar temperature dependence as that of the αcore process for ILC12, 14, 16 but shifts to higher temperature for ILC8 and 10. For ILC12, 14, 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, 10 the DC conductivity behavior is similar to ionic liquids, where the conductivity is coupled with structural relaxation. Small-Angle X-ray (SAXS) investigations reveal that both the intercolumnar distance and disorder coherence length increase with alkyl chain length, conversely the DC conductivity decreases monotonically. T2 - 11th IDS conference 2022 CY - San Sebastian, Spain DA - 03.09.2022 KW - Glass transition KW - Conductivity KW - Fast Scanning Calorimetry KW - Dynamics PY - 2022 AN - OPUS4-55878 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas T1 - Confinement induced relaxations and phase behavior of a nanoconfined ionic liquid crystal N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing phase transition behaviors and relaxation dynamics. Here in, we investigate the molecular dynamics and electrical conductivity of a linear shaped guanidinium based ILC confined in self-ordered nano porous alumina oxide membranes of pore size ranging from 180nm down to 25nm by employing broadband dielectric spectroscopy (BDS) and calorimetry. Calorimetric investigation reveals a complete suppression of the columnar – isotropic transition, while the plastic crystalline – columnar transition temperature decreases with inverse pore size and deviates from the Gibbs – Thomson equation. For the bulk case, BDS detects two relaxation modes in the crystalline phase, the  relaxation and the α1 relaxation, and two relaxation modes in the columnar phase, the α2 and α3 relaxation. For the confined case, all relaxation modes slow down compared to the bulk. However, for the least pore size (25 nm), the α2 relaxation is absent. We discuss the possible molecular origins of the different relaxation modes observed. For the bulk ILC, a clear jump of 4 orders of magnitude in the absolute values of DC conductivity occurs at the transition from the plastic crystalline to hexagonal columnar phase, for the confined ILC, this transition is smooth. DC conductivity is reduced for the confined case, except for the 25nm, where the values is similar to the bulk. T2 - 11th IDS conference 2022 CY - San Sebastian, Spain DA - 03.09.2022 KW - Ionic Liquid crystals KW - Nanoconfinement KW - Conductivity PY - 2022 AN - OPUS4-55879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroyuk, O. A1 - Raievska, O. A1 - Barabash, A. A1 - Batentschuk, M. A1 - Osvet, A. A1 - Fiedler, Saskia A1 - Resch-Genger, Ute A1 - Hauch, J. A1 - Brabec, C. J. T1 - “Green” Synthesis of Highly Luminescent Lead-Free Cs2AgxNa1-xBiyIn1-yCl6 Perovskites N2 - A new “green” and mild synthesis of highly stable microcrystalline Cs2AgxNa1-xBiyIn1-yCl6 (CANBIC) perovskites under ambient conditions was developed that is scalable to the multi-gram production. Under UV illumination, the CANBIC perovskites emit intense broadband photoluminescence (PL) with a quantum yield (QY) of 92% observed for x = 0.35 and y = 0.01-0.02. The combination of strong UV absorbance and broadband visible emission, high PL QY, and long PL lifetimes of up to 1.4 μs, along with an outstanding stability makes these CANBICs a promising material class for many optical applications. KW - Fluorescence KW - Perovskites KW - Solar cell KW - Automated synthesis KW - Green synthesis KW - Quantum yield KW - Integrating sphere spectroscopy KW - Absolute fluorescence KW - Quality assurance KW - Nano KW - Particle KW - Application KW - Semiconductor KW - Quantum dot KW - Renewable energy PY - 2022 DO - https://doi.org/10.1039/d2tc02055f SN - 2050-7526 VL - 10 IS - 27 SP - 9938 EP - 9944 PB - Royal Society of Chemistry AN - OPUS4-55453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Yang, J. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Ou, J. T1 - Fluorescence temperature sensing of NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ nanoparticles at low and high temperatures N2 - NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ upconversion nanoparticles (UCNPs) were prepared using a solvothermal method, and the effects of key factors such as the content of sensitiser Nd 3+ and Yb3+ on their luminescence properties were investigated. The nanoparticles are homogeneous in size and well dispersed. Under 808 nm excitation, it can produce strong upconversion fluorescence. At the same time, the nanoparticles have good temperature-sensing properties at the thermally coupled energy levels of 700 nm and 646 nm for Tm3+. Using its fluorescence intensity ratio (FIR), accurate temperature measurements can be performed, and it has been found that it exhibits different temperature sensing properties in low and high-temperature regions. The maximum relative sensitivity was found to be 0.88% K-1 and 1.89% K-1 for the lowtemperature region of 285 K-345 K and the high-temperature region of 345 K-495 K. The nanoparticles were applied to the internal temperature measurement of lithium batteries and the actual high-temperature environment, respectively, and were found to have good temperature measurementt performance. KW - Fluorescence KW - Sensor KW - Temperature KW - Ratiometric KW - Lanthanide KW - Quantum yield KW - Integrating sphere spectroscopy KW - Absolute fluorescence KW - Quality assurance KW - Nano KW - Particle KW - Application KW - Upconversion nanoparticle PY - 2022 DO - https://doi.org/10.1088/1361-6528/ac84e4 SN - 1361-6528 VL - 33 IS - 34 SP - 1 EP - 15 PB - IOP Publishing CY - Bristol AN - OPUS4-55454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Pellegrino, Francesco A1 - Maurino, V. T1 - Morphological Characterization and Chemical Identification of TiO2 Nanoparticles Doped with Ultrafine Metal Particles for Enhanced Photocatalytical Activity N2 - Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy (SEM) coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, Au, Rh, Pd) and metal concentrations are discussed. T2 - Microscopy and Microanalysis 2022 CY - Portland, OR, USA DA - 31.07.2022 KW - Nanoparticles KW - Me-TiO2 KW - Photocatalysis KW - Morpho-chemical characterization KW - Shape KW - SEM/EDS PY - 2022 AN - OPUS4-55541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henning, L. M. A1 - Müller, J. T. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Schmidt, J. A1 - Bekheet, M. F. A1 - Gurlo, A. A1 - Simon, U. T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3 ), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling. KW - SAXS KW - Hierarchically porous KW - Silica KW - Water filtration PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928 DO - https://doi.org/10.1039/D2NA00368F SN - 2516-0230 SP - 1 EP - 17 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-55592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tavernaro, Isabella A1 - Nirmalananthan-Budau, Nithiya A1 - Rühle, Bastian A1 - Geißler, Daniel A1 - Resch-Genger, Ute T1 - Quantification of surface functional groups on inorganic and organic nanomaterials using cleavable reporters N2 - Engineered nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing and electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties. Especially, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups and ligands, is an important key driver for the performance, stability, and processibility of NM, as well as their interaction with the environment. Thus, methods for functional group quantification can foster the sustainable development of functional and safe(r) NM. Aiming at the development of simple, versatile and multimodal tools for the quantification of common bioanalytically relevant functional groups, we designed a catch-and-release assay based on cleavable probes that enable the quantification of the cleaved-off reporters in the supernatant after particle separation. Thus, the approach circumvents interferences resulting from particle light scattering and sample-inherent absorption or emission. To study the potential of the assay, commercially available and in-house synthesized aminated and carboxylated polymer and silica nanoparticles of different functional group densities were tested. Our cleavable probe strategy can be easily adapted to other analytical techniques requiring different reporters, or to different types of linkers that can be cleaved thermally, photochemically, or by variation of pH, utilizing well-established chemistry. In addition, it can contribute to the development of multi-method characterization strategies to provide a more detailed picture of the intrinsic physicochemical property - performance/safety relationships and thus can support the design of tailored nanomaterials with better controlled properties. T2 - E-MRS Spring Meeting 2021 / ALTECH 2021 - Analytical techniques for precise characterization of nanomaterials CY - Online meeting DA - 31.05.2021 KW - Surface modified nano- and microparticles KW - Optical assays KW - Particle surface analysis KW - Surface functional group quantification PY - 2021 AN - OPUS4-55596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Srivastava, Priyanka A1 - Tavernaro, Isabella A1 - Scholtz, Lena A1 - Resch-Genger, Ute T1 - Multi-color nanosensors for ratiometric measurements of acidic, neutral, and basic pH based on silica and polystyrene particles N2 - pH presents one of the most important analytes in the life and material sciences, indicating, e.g., diseases and corrosion processes. This includes the optical monitoring of pH in living cells for studying cellular internalization pathways, such as phagocytosis, endocytosis, and receptor mediated internalization with the aid of molecular and nanoscale fluorescent sensors. Nanoparticle (NP)-based sensors, that are labelled or stained with a multitude of sensor dyes, have several advantages as compared to conventional molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. Versatile templates and carriers for the fabrication of nanosensors by staining and/or labelling with different fluorophores and sensor molecules are surface-functionalized particles like silica (SiO2) and polystyrene (PS) particles. Here we present a platform of blue-red-green fluorescent pH nanosensors for the measurement of acidic, neutral, and basic pH utilizing both types of matrices and two spectrally distinguishable sensor dyes with an integrated reference dye and demonstrate its applicability for cellular studies. T2 - E-MRS Spring Meeting 2022 CY - Online meeting DA - 30.05.2022 KW - Nanosensors KW - pH sensing KW - Silica- and polystyrene particles KW - Ratiometric sensors KW - Fluorescence PY - 2022 AN - OPUS4-55597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bartczak, D. A1 - Hodoroaba, Vasile-Dan T1 - Report on the development and validation of the reference material candidates with non-spherical shape, non-monodisperse size distributions and accurate nanoparticle concentrations N2 - One aim of the EMPIR nPSize project 17NRM04 was to develop and validate three classes of candidate reference (test) materials (RTMs), with i) well-defined non-spherical shape, ii) relatively high polydispersity index, and iii) accurate particle concentrations. To fulfil the requirements of the project, 11 different types of materials were prepared. Following the initial assessment of the materials suitability, nPSize5_PT_UNITO, nPSize6_AC_UNITO and nPSize7_GN_CEA materials were found unsuitable for the project, due to various reasons. PT material was deemed unsuitable due to its predominantly agglomerated nature. AC material contained relatively high amount of impurities (other particle forms). GN material was found too heterogeneous in both the length and width for the purpose of the project. The remaining 8 candidate RTMs were assessed for their homogeneity and stability and used for successful delivery of the associated activities within the nPSize project. KW - Nanoparticles KW - Particle size distribution KW - Reference materials KW - Non-spherical shape KW - EMPIR nPSize KW - Electron microscopy KW - AFM KW - SAXS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556015 DO - https://doi.org/10.5281/zenodo.7016466 SP - 1 EP - 22 PB - Zenodo CY - Geneva AN - OPUS4-55601 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Terborg, R. A1 - Hodoroaba, Vasile-Dan A1 - Kim, K. J. T1 - Determination of Thin Film Thickness and Composition using Energy Dispersive EPMA N2 - Electron Probe Microanalysis (EPMA) provides a non-destructive approach in the dedicated thin film analysis mode with the commercial StrataGem software. Recently, the open-source programme BadgerFilm by Moy and Fournelle became available. Similarly to StrataGem, it is based on the algorithm of Pouchou and Pichoir and needs intensity ratios of the unknown sample and standards (k-values). We have evaluated the k-values measured for the FeNi and SiGe film systems using the BadgerFilm software package and compared the thickness and composition with the results obtained with the established StrataGem software and other reference methods. The thicknesses of the SiGe films obtained by the BadgerFilm software agree within 20% with the StrataGem and TEM results; the elemental compositions BadgerFilm-StrataGEM agree within 2% with one exception (9%). T2 - Microscopy and Microanalysis 2022 CY - Portland, OR, USA DA - 31.07.2022 KW - Thin films KW - Thickness KW - Elemental composition KW - FeNi KW - SiGe KW - BadgerFilm KW - Electron Probe Microanalysis (EPMA) PY - 2022 AN - OPUS4-55522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Jaenisch, Gerd-Rüdiger A1 - Pavasaryte, Lina A1 - Funk, Alexander T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed. KW - Non-destructive testing KW - Two-photon polymerization KW - X-ray microscopy KW - XCT KW - 2PP KW - Direct laser writing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525 DO - https://doi.org/10.3390/app122010488 VL - 12 IS - 20 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-56052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüdicke, M. G. A1 - Hildebrandt, Jana A1 - Schindler, C. A1 - Sperling, R. A. A1 - Maskos, M. T1 - Automated QuantumDots Purification via Solid Phase Extraction N2 - The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types. KW - Quantum Dots KW - Purification PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559590 DO - https://doi.org/10.3390/nano12121983 SN - 2079-4991 VL - 12 IS - 12 PB - MDPI CY - Basel AN - OPUS4-55959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erning, Johann Wilhelm T1 - Anforderungen an den Einsatz von Metallen im Trinkwasser N2 - Die Trinkwasserverordnung gibt regulatorische Vorgaben zum Werkstoffeinsatz. Daneben existieren normative Hinweise zur Beständigkeit der Werkstoffe. Das Zusammenspiel der unterschiedlichen Vorgaben wird dargestellt und diskutiert T2 - Korrosionsverhalten bleifreier Kupfer-Zink-Legierungen im Kontakt mit Trinkwasser CY - Dresden, Germany DA - 11.10.2022 KW - Korrosion KW - Trinkwasser KW - Hygiene KW - Werkstoffe PY - 2022 AN - OPUS4-55982 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Straße, Anne A1 - Bakir, Nasim A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Preliminary study to investigate the applicability of optical strain measurement technique for the detection of hot cracks in laser metal deposited layers N2 - Laser metal deposition (LMD) as an additive manufacturing technique became increasingly important in recent years and thus the demand for component safety. This is the reason, for the need for reliable in-situ defect detection techniques. For laser beam weld seams an optical measurement technique based on an optical flow algorithm was successfully used to define the critical straining conditions that lead to hot cracking. This algorithm was adapted for bead-on-plate weld seams on LMD deposited layers of IN718 alloy while performing external strain on the specimen in an externally loaded hot cacking test facility. The resulting transversal hot cracks along the weld seam were localized via X-Ray inspection and the type of cracking confirmed by Scanning Electron Microscopy (SEM). The strain distribution was measured in the vicinity of the solidification front and correlated to the detected hot cracks. Based on the results this technique could be adopted for LMD experiments. T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022] CY - Fürth, Germany DA - 04.09.2022 KW - Strain measurement KW - Optical flow KW - Laser Metal Deposition (LMD) KW - Critical strain PY - 2022 AN - OPUS4-55642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pütz, E. A1 - Smales, Glen Jacob A1 - Jegel, O. A1 - Emmerling, Franziska A1 - Tremel, W. T1 - Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity N2 - Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as H2O2 by oxidizing an organic substrate. We show that the chemical activity of CeO2−x nanoparticles in haloperoxidase- and peroxidaselike reactions scales with their active surface area, their surface charge, given by the ζ-potential, and their surface defects (via the Ce3+/Ce4+ ratio). Haloperoxidase-like reactions are controlled through the ζ-potential as they involve the adsorption of charged halide anions to the CeO2 surface, whereas peroxidase-like reactions without charged substrates are controlled through the specific surface area SBET. Mesoporous CeO2−x particles, with large surface areas, were prepared via template-free hydrothermal reactions and characterized by small-angle X-ray scattering. Surface area, ζ-potential and the Ce3+/Ce4+ ratio are controlled in a simple and predictable manner by the synthesis time of the hydrothermal reaction as demonstrated by X-ray photoelectron spectroscopy, sorption and ζ-potential measurements. The surface area increased with synthesis time, whilst the Ce3+/Ce4+ ratio scales inversely with decreasing ζ-potential. In this way the catalytic activity of mesoporous CeO2−x particles could be tailored selectively for haloperoxidase- and peroxidase-like reactions. The ease of tuning the surface properties of mesoporous CeO2x particles by varying the synthesis time makes the synthesis a powerful general tool for the preparation of nanocatalysts according to individual needs. KW - SAXS KW - Ceria KW - Zeta potential PY - 2022 DO - https://doi.org/10.1039/D2NR03172H SP - 1 EP - 12 PB - Royal Society of Chemistry AN - OPUS4-55649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, R. A1 - Fa, X. A1 - Yang, J. A1 - Cheng, Z. A1 - Qiao, X. A1 - Ou, J. A1 - Würth, Christian A1 - Resch-Genger, Ute T1 - Core−Shell NaYF4:Yb3+/Tm3+@NaGdF4:Ce3+/Eu3+ Nanoparticles for Upconversion and Downconversion Dual-Mode Fluorescence-Based Temperature Sensing N2 - NaYF4 as the core and NaGdF4 as the outer layer were used to obtain NaYF4:Yb3+/Tm3+@NaYF4:Ce3+/Eu3+ nanoparticles. Physical and morphological investigations indicated that the obtained nanoparticles were prepared in a hexagonal shape, with the NaGdF4 shell layer uniformly encapsulated on the NaYF4 core. Strong Tm3+ upconversion emission peaks were observed for a 980-nm-laser-excited sample, while strong Eu3+ downconversion emission peaks were observed for a 254-nm-laser-excited sample. By zonal doping of Tm3+ and Eu3+, their fluorescence intensity can be significantly increased; more importantly, simultaneous temperature measurements with dual-mode upconversion/downconversion can be achieved. The temperature measurement properties of the dual mode were also investigated, and it was discovered that the upconversion 3F3 → 3H6 and 1G4 → 3F4 thermocouple energy levels gave the best temperature measurements with maximum absolute and relative sensitivities of 0.0877 K−1 and 1.95% K−1, respectively, which are better than the current temperature measurement sensitivities of most rare-earth-based materials. This material was prepared as fiber-optic temperature-sensing probes to detect the temperature in the environment in real time and was found to perform excellently for temperature measurement. KW - Upconversion nanoparticle KW - Lanthanide KW - Sensing; temperature KW - Photophysics PY - 2022 DO - https://doi.org/10.1021/acsanm.2c01611 VL - 5 IS - 7 SP - 9266 EP - 9276 PB - American Chemical Society AN - OPUS4-55363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Monks, M.-J. A1 - Würth, Christian A1 - Kemnitz, Erhard A1 - Resch-Genger, Ute T1 - Dopant ion concentration-dependent upconversion luminescence of cubic SrF2:Yb3+, Er3+ nanocrystals prepared by a fluorolytic sol–gel method N2 - A fluorolytic sol–gel method was used for the fast and simple synthesis of small cubic-phase SrF2:Yb3+, Er3+ upconversion (UC) nanocrystals (UCNC) of different composition at room temperature. Systematic studies of the crystal phase and particle size of this Yb3+,Er3+-concentration series as well as excitation power density (P)-dependent UC luminescence (UCL) spectra, UCL quantum yields (ΦUCL), and UCL decay kinetics yielded maximum UCL performance for doping amounts of Yb3+ of 13.5% and Er3+ of 1.3% in the studied doping and P-range (30–400 W cm−2). Furthermore, ΦUCL were determined to be similar to popular β-NaYF4:Yb3+,Er3+. The relative spectral UCL distributions revealed that all UCNC show a strong red emission in the studied doping and P-range (30–400 W cm−2) and suggest that the UCL quenching pathway for unshelled cubic-phase SrF2:Yb3+,Er3+ UCNC differs from the commonly accepted population and depopulation pathways of β-NaYF4:Yb3+,Er3+ UCNC. In SrF2:Yb3+,Er3+ UCNC the 4S3/2 → 4I13/2 transition exhibits a notably stronger sensitivity towards P and reveals increasing values for decreasing Yb3+–Yb3+ distances while the 4I9/2 → 4I15/2 transition is significantly less affected by P and energy migration facilitated UCL quenching. These results emphasize the complexity of the UC processes and the decisive role of the crystal phase and symmetry of the host lattice on the operative UCL quenching mechanism in addition to surface effects. Moreover, the room temperature UCNC synthesis enabled a systematic investigation of the influence of the calcination temperature on the crystal phase of powder-UCNC and the associated UCL properties. Calcination studies of solid UCNC of optimized doping concentration in the temperature range of 175 °C and 800 °C showed the beneficial influence of temperature- induced healing of crystal defects on UCL and the onset of a phase separation connected with the oxygenation of the lanthanide ions at elevated temperature. This further emphasizes the sensitivity of the UC process to the crystal phase and quality of the host matrix. KW - Upconversion nanoparticle KW - Lanthanide KW - Photophysics KW - Synthesis PY - 2022 DO - https://doi.org/10.1039/d2nr02337g SP - 1 EP - 10 PB - Royal Society of Chemistry AN - OPUS4-55364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -