TY - CONF A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Falkenhagen, Jana T1 - Combined impact of UV radiation and nitric acid (HNO3) on HDPE jerrycans – comparison of outdoor and lab test N2 - A damaging action of HNO3-55% only occurs in combination with its decomposition into nitrous gases, which can be caused by UV radiation. In a laboratory test, transparent HDPE jerrycans have been exposed to both UV radiation and 55 wt-% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The respective damages are compared with FTIR spectroscopy in ATR and HT-gel permeation chromatography (GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. The gradual increase in oxidative damage shows the good reproducibility of the lab exposure. The decomposition of nitric acid into nitrous gases by UV radiation – as well as the jerrycan oxidation – is also observed at lower HNO3 concentration (28 wt- %). Similar results are obtained after outdoor tests. Again, the damage occurs only after combined exposure, in contrast to the exposures to UV only and to HNO3 only, which were conducted in parallel. Outdoor exposures are most readily accepted as they represent possible end-use conditions. However, the reproducibility of these exposures is poor due to the large temporal variations in weather. There are also several safety risks, which is why the number of replicates remains limited. Since the outdoor and lab exposure tests show the same qualitative results, it is appropriate to conduct systematic studies in the laboratory. After 6 days of lab exposure, the oxidation damage is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. It should be noted that this amount can also occur in two sunny weeks. T2 - 24th iapri World Packaging Conference CY - Valencia, Spain DA - 17.06.2024 KW - Ppolyethylene KW - UV exposure KW - Nitric acid KW - Oxidation PY - 2024 VL - 2 SP - 30 EP - 37 PB - ITENE AN - OPUS4-60414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Malpass-Evans, R. A1 - McKeown, N. A1 - Jalarvo, N. A1 - Tyagi, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering – bend fluctuations and signature of methyl group rotation N2 - Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer–Emmett–Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bendand-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EATB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure. KW - Polymers of Intrinsic Microporosity KW - Neutron Scattering PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604114 DO - https://doi.org/10.1039/d4sm00520a SP - 1 EP - 11 PB - RSC AN - OPUS4-60411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cakir, Cafer Tufan A1 - Bogoclu, Can A1 - Emmerling, Franziska A1 - Streli, Christina A1 - Guilherme Buzanich, Ana A1 - Radtke, Martin T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications. KW - Machine Learning KW - GE-XANES KW - Bayesian Optimization PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955 DO - https://doi.org/10.1088/2632-2153/ad4253 VL - 5 IS - 2 SP - 1 EP - 12 PB - IOP Publishing AN - OPUS4-60395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Guiping A1 - Liu, Ye A1 - Schultz, Thorsten A1 - Exner, Moritz A1 - Muydinov, Ruslan A1 - Wang, Hui A1 - Scheurell, Kerstin A1 - Huang, Jieyang A1 - Szymoniak, Paulina A1 - Pinna, Nicola A1 - Koch, Norbert A1 - Adelhelm, Philipp A1 - Bojdys, Michael J. T1 - One‐Pot Synthesis of High‐Capacity Sulfur Cathodes via In‐Situ Polymerization of a Porous Imine‐Based Polymer N2 - AbstractLithium‐ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur‐based cathodes, offering a high theoretical capacity of 1675 mAh g−1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state‐of‐the‐art sulfur‐based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur‘s mobility leads to battery degradation—an effect known as the “sulfur‐shuttle”. This study introduces a solution by developing a microporous, covalently‐bonded, imine‐based polymer network grown in situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li‐ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1 C (1360 mAh g−1) to 3 C (807 mAh g−1). Demonstrating a high‐performance, sustainable sulfur cathode produced via a simple one‐pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal‐based cathodes. KW - In-situ polymerization KW - Sulfur cathodes PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604215 DO - https://doi.org/10.1002/anie.202400382 SN - 1433-7851 SP - 1 EP - 11 PB - Wiley VHC-Verlag AN - OPUS4-60421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Das, Prasenjit A1 - Chakraborty, Gouri A1 - Friese, Nico A1 - Roeser, Jérôme A1 - Prinz, Carsten A1 - Emmerling, Franziska A1 - Schmidt, Johannes A1 - Thomas, Arne T1 - Heteropolyaromatic Covalent Organic Frameworks via One-Pot Multicomponent Reactions N2 - Multicomponent reactions (MCRs) offer a platform to create different chemical structures and linkages for highly stable covalent organic frameworks (COFs). As an illustrative example, the multicomponent Povarov reaction generates 2,4-phenylquinoline from aldehydes and amines in the presence of electron-rich alkenes. In this study, we introduce a new domino reaction to generate unprecedented 2,3-phenylquinoline COFs in the presence of epoxystyrene. This work thus presents, for the first time, structural isomeric COFs produced by multicomponent domino and Povarov reactions. Furthermore, 2,3-phenylquinolines can undergo a Scholl reaction to form extended aromatic linkages. With this approach, we synthesize two thermally and chemically stable MCR-COFs and two heteropolyaromatic COFs using both domino and in situ domino and Scholl reactions. The structure and properties of these COFs are compared with the corresponding 2,4-phenylquinoline-linked COF and imine-COF, and their activity toward benzene and cyclohexane sorption and separation is investigated. The position of the pendant phenyl groups within the COF pore plays a crucial role in facilitating the industrially important sorption and separation of benzene over cyclohexane. This study opens a new avenue to construct heteropolyaromatic COFs via MCR reactions. KW - COF PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604038 DO - https://doi.org/10.1021/jacs.4c02551 SP - 1 EP - 9 PB - American Chemical Society (ACS) AN - OPUS4-60403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dudziak, Mateusz A1 - Bhatia, Riya A1 - Dey, R. A1 - Falkenhagen, Jana A1 - Ullrich, M. S. A1 - Thomsen, C. A1 - Schartel, Bernhard T1 - Wastewater phosphorus enriched algae as a sustainable flame retardant in polylactide N2 - Revolutionizing our polymer industry for adaption to a sustainable carbon circular economy has become one of today’s most demanding challenges. Exploiting renewable resources to replace fossil-fuel—based plastics with biopolymers such as poly(lactic acid) (PLA) is inevitable while using waste streams as a raw material resource at least is promising. When it comes to using PLA as technical polymer, its high flammability must be addressed by flame retardants compatible with the thermoplastic processing of PLA and its compostability. This study proposes microalgae enriched with phosphorus from wastewater (P-Algae) as an elegant way towards a kind of sustainable organophosphorus flame retardant. The concept is demonstrated by investigating the processing, pyrolysis, flammability, and fire behavior of PLA/P-Algae, while varying the P-Algae content and comparing P-Algae with four alternative bio-fillers (phosphorylated lignin, biochar, thermally treated sewage sludge, and metal phytate) with different P-contents as meaningful benchmarks. KW - PLA KW - Flame Retardancy KW - Phosphorylated Algae KW - Wastewater flame retardants KW - Zink phytate KW - Phosphorylated lignin KW - Thermally treated sludge PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604150 DO - https://doi.org/10.1016/j.polymdegradstab.2024.110885 SN - 1873-2321 SN - 0141-3910 VL - 227 SP - 1 EP - 11 PB - Elsevier Ltd. AN - OPUS4-60415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Glazyrin, Konstantin A1 - Spektor, Kristina A1 - Bykov, Maxim A1 - Dong, Weiwei A1 - Yu, Ji‐Hun Yu A1 - Yang, Sangsun Yang A1 - Lee, Jai‐Sung Lee A1 - Divinski, Sergiy V. A1 - Hanfland, Michael A1 - Yusenko, Kirill V. T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage. KW - XRD KW - HIgh entropy, KW - Cantor KW - Alloys KW - Synchrotron PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170 DO - https://doi.org/10.1002/advs.202401741 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-60417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pallasch, Sebastian M. A1 - Bhosale, Manik A1 - Smales, Glen J. A1 - Schmidt, Caroline A1 - Riedel, Sibylle A1 - Zhao-Karger, Zhirong A1 - Esser, Birgit A1 - Dumele, Oliver T1 - Porous Azatruxene Covalent Organic Frameworks for Anion Insertion in Battery Cells N2 - Covalent organic frameworks (COFs) containing well-defined redox-active groups have become competitive materials for next-generation batteries. Although high potentials and rate performance can be expected, only a few examples of p-type COFs have been reported for charge storage to date with even fewer examples on the use of COFs in multivalent ion batteries. Herein, we report the synthesis of a p-type highly porous and crystalline azatruxene-based COF and its application as a positive electrode material in Li- and Mg-based batteries. When this material is used in Li-based half cells as a COF/carbon nanotube (CNT) electrode, a discharge potential of 3.9 V is obtained with discharge capacities of up to 70 mAh g−1 at a 2 C rate. In Mg batteries using a tetrakis(hexafluoroisopropyloxy)borate electrolyte, cycling proceeds with an averge discharge voltage of 2.9 V. Even at a fast current rate of 5 C, the capacity retention amounts to 84% over 1000 cycles. KW - COFs PY - 2024 DO - https://doi.org/10.1021/jacs.4c04044 VL - 146 IS - 25 SP - 17318 EP - 17324 PB - Journal of the American Chemical Society AN - OPUS4-60419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Matthews, Lauren T1 - Breaking the Wall of Rapid Diagnostics N2 - In this short presentation the diagnostics, biomarkers and analysis are interrelated. The specificity and sensitivity of the DNA structures as well as the high-throughput option of the nanopore sensing are discussed. T2 - Falling Walls Lab Berlin-Adlershof CY - Berlin, Germany DA - 21.09.2023 KW - Nanopipettes KW - Sensing KW - Diagnosis KW - DNA structures PY - 2023 AN - OPUS4-60450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Elisabeth A1 - Weise, Matthias A1 - Stockmann, Jörg M. A1 - Radnik, Jörg A1 - Sahre, Mario A1 - Lange, Thorid A1 - Hodoroaba, Dan T1 - Towards a high-entropy alloy thin-film reference material N2 - Analyzing materials composed of multiple elements with spectroscopic techniques such as X-ray Photoelectron Spectroscopy (XPS), Auger-Electron Spectroscopy (AES) or Electron Probe Microanalysis (EPMA), can be challenging due to spectral overlap. Moreover, each analytical method introduces its own set of challenges, e.g., the strong secondary fluorescence effect for neighbor elements in EPMA, thus, making the accurate elemental quantification in such materials difficult. When the material is available as thin film, additional constraints are inherently present. To provide a reference material for these analytical challenges high entropy alloys (HEAs) are excellent candidates. Currently, there is no thin film reference available containing more than 2 elements. Unlike traditional alloys, which typically consist of one or two main elements and smaller amounts of secondary elements, HEAs are characterized by the presence of multiple principal elements in almost equal proportions. This unique composition results in a high degree of disorder at the atomic level, leading to exceptional mechanical, physical, and often unexpected properties. HEAs have garnered significant attention in materials science and engineering due to their potential applications in a wide range of industries, from aerospace and automotive to electronics and renewable energy. For the preparation of a dedicated thin film reference material, we have chosen to prepare HEAs by magnetron sputtering, since it is not associated with elemental segregation that may occur due to the high configurational entropy of HEAs, which promotes atomic rearrangements. Our goal was to prepare films with a homogeneous thickness and defined chemical composition to be analyzed by various methods dedicated to surface analysis. The material, consisting of titanium, chromium, manganese, iron, and nickel was deposited as film on silicon substrates - to our knowledge the first HEA thin film of this type reported in literature. A set of different thickness of the films was chosen, on the one hand to facilitate the analysis with different techniques, and on the other side to evaluate the limitations of the respective methods. The films morphology was characterized as prepared by SEM followed by the analysis of their 2D compositional homogeneity by EDX, XRF, ToF-SIMS and XPS. in-depth chemical composition was evaluated by ToF-SIMS and AES. The outcomes of analyzing the initial batches of films will be presented. T2 - European Conference on Applications Surface and Interface Analysis (ECASIA 2024) CY - Gothenburg, Sweden DA - 10.06.2024 KW - High-entropy alloy KW - Thin film KW - Magnetron sputtering PY - 2024 AN - OPUS4-60455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sänger, Johanna C. A1 - Riechers, Birte A1 - Pauw, Brian R. A1 - Maaß, Robert A1 - Günster, Jens T1 - Microplastic response of 2PP‐printed ceramics N2 - AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications. KW - Manufacturing KW - Mechanical properties KW - Microstructure KW - Plasticity KW - Zirconia: yttria stabilized PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605176 DO - https://doi.org/10.1111/jace.19849 SN - 1551-2916 SP - 1 EP - 10 PB - Wiley CY - Oxford [u.a.] AN - OPUS4-60517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madbouly, Loay Akmal A1 - Mrkwitschka, Paul A1 - Schusterbauer, Robert A1 - Stockmann, Jörg Manfred A1 - Jones, E. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Chemical Analysis of Functionalized Graphene along the Production Chain N2 - Graphene has been commercialized for over a decade. It is usually used in the form of suspensions or inks. In this study, we analyze the starting material for commercial functionalized graphene (FG) solutions and inks as well as their starting material (FG powders) using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-Ray spectroscopy (EDX), time of flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Graphene was functionalized with fluorine, oxygen, ammonia, and carboxylic acid. Our results suggest a significant effect of water and commercial resins on the presence as well as the morphological behavior of graphene and associated functionalized group. For example, XPS analysis shows some significant differences between the solutions and the starting materials (powders). These changes can be explained by the location of the functionalization at the outer most surface as indicated by Chemello et al. T2 - European Conference on Applications of Surface and Interface Analysis (ECASIA 2024) CY - Gothenburg, Sweden DA - 09.06.2024 KW - Functionalized graphene KW - Commercial graphene KW - Graphene inks PY - 2024 AN - OPUS4-60446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madbouly, Loay Akmal A1 - Mrkwitschka, Paul A1 - Schusterbauer, Robert A1 - Schusterbauer, Jörg Manfred A1 - Jones,, E. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Chemical Analysis of Functionalized Graphene along the Production Chain N2 - Graphene has been commercialized for over a decade. It is usually used in the form of suspensions or inks. In this study, we analyze the starting material for commercial functionalized graphene (FG) solutions and inks as well as their starting material (FG powders) using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-Ray spectroscopy (EDX), time of flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Graphene was functionalized with fluorine, oxygen, ammonia, and carboxylic acid. Our results suggest a significant effect of water and commercial resins on the presence as well as the morphological behavior of graphene and associated functionalized group. For example, XPS analysis shows some significant differences between the solutions and the starting materials (powders). These changes can be explained by the location of the functionalization at the outer most surface as indicated by Chemello et al. T2 - MaterialsWeek 2024 CY - Limassol, Cyprus DA - 17.06.2024 KW - Functionalized graphene KW - Commercial graphene KW - Graphene inks PY - 2024 AN - OPUS4-60448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Hodoroaba, Vasile-Dan A1 - Pellegrino, Francesco A1 - Rossi, Andrea A1 - Jones, Elliot T1 - Towards automated analysis of the lateral dimensions of graphene oxide flakes N2 - Graphene and graphene-oxide (GO) are advanced materials which – similar to other graphene-related 2D materials (GR-2M) - are already used for instance in catalysis processes, biomedical applications, in inks and resins, or as composite materials for the aviation industry. The lateral/structural characterization of graphene oxide (GO) flakes is a challenging task, with steps like sample preparation, representative image selection and exact determination of the particle size distribution of well-defined size and shape descriptors being crucial for an accurate analysis. To ensure that safe-by-design principles are met within the various application fields, the commercial material must be thoroughly characterized and specified through well-known and standardized procedures. GO flakes with different degrees of complexity were selected to assess the requirements for an accurate evaluation of their physico-chemical properties. These samples show inherent features with complex nanoscale characteristics such as porosity and edge roughness; further, the lateral size (quantified via equivalent circular diameter (ECD), minimum Feret and maximum Feret) of isolated and overlapping particles deposited on a substrate span over several orders of magnitude (nano to micron scale). The samples showed different degrees of agglomeration (and possible aggregation) with sizes ranging between submicron to a few tens of micrometers. One focus is the automated segmentation and evaluation of images obtained by electron microscopy. The GO samples appear translucent with well-defined contrast between single and overlapping flakes both with the secondary electron detector of type InLens as well as with SEM in the transmission mode (STEM) utilizing a dedicated sample holder. To this end it is of utmost importance for the accurate image segmentation to carefully select thresholds both manually and through semi-automatic approaches using well-known threshold algorithms such as “IsoData” and pre-defined segmentation applications such as the ParticleSizer software package. Further specific challenges in identifying and extracting key features of selected graphene oxide flakes are being discussed and approaches towards accurate and representative characterization are presented. T2 - E-MRS 2024 Spring Meeting CY - Strasbourg, France DA - 27.05.2024 KW - Graphene /-oxide KW - Morphology KW - Electron microscopy KW - Imaging KW - Advanced materials PY - 2024 AN - OPUS4-60435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Matthews, Lauren A1 - Sahre, Mario A1 - Hesse, R. A1 - Schusterbauer, Robert A1 - Grant, M. A1 - Agudo Jacome, Leonardo A1 - Albrecht, T. A1 - Hodoroaba, Vasile-Dan T1 - Approaches to Surface Analysis of Modified Quartz Nanopipettes N2 - Nanopipettes are a type of solid-state nanopore with needle-like geometry. Their applications range from imaging, sensing, diagnostics, and use as injectors. The response of nanopipette sensors is highly dependent on the size, geometry and chemical properties of the sensing region. As they are increasingly tuned and modified for specific analytes, a better understanding of the surface chemistry and morphology of the inner channel is necessary. With the aim of developing a comprehensive approach for characterisation of such nanopipettes, this research focuses on combining surface-sensitive analysis methods with advanced sample preparation techniques. Quartz substrates were modified by gas phase silanization, a well-utilised technique in the field to enhance performance of nanopipettes, and further functionalised with a metal bis thiolate complex, to aid in chemical analysis. The sample characterisation involved scanning electron microscopy (SEM), low-energy dispersive x-ray spectroscopy (EDX), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Using focused ion beam (FIB) milling under gentle conditions, the inner surface of quartz nanopipettes was exposed whilst preserving the integrity of the overall structure (see figure). Owing to the challenging analysis conditions, modification and analysis of flat quartz substrates has been performed in parallel for optimisation purposes. The results demonstrate the first steps towards full characterisation of nanopipettes at the nanoscale, notably with access to the inner channel. The methods used here can be applied to gain further understanding of the response of these sensors to complex analytes and allow for the study of different surface functionalisations at the all-important sensing region. T2 - European Conference on Applications of Surface and Interface Analysis (ECASIA 2024) CY - Gothenburg, Sweden DA - 09.06.2024 KW - Quartz nanopipettes KW - Nanopipette modification KW - Silanization KW - Surface analysis KW - Focussed ion beam PY - 2024 AN - OPUS4-60447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Matthews, Lauren A1 - Sahre, Mario A1 - Hesse, R. A1 - Schusterbauer, Robert A1 - Grant, M. A1 - Agudo Jacome, Leonardo A1 - Albrecht, T. A1 - Hodoroaba, Vasile-Dan T1 - Approaches to Surface Analysis of Modified Quartz Nanopipettes N2 - Nanopipettes are a type of solid-state nanopore with needle-like geometry. Their applications range from imaging, sensing, diagnostics, and use as injectors. The response of nanopipette sensors is highly dependent on the size, geometry and chemical properties of the sensing region. As nanopipettes are increasingly tuned and modified for specific analytes, a better understanding of the surface chemistry and morphology of the inner channel is necessary. For exploring these effects, quartz nanopipettes were modified by gas phase silanization, a well-utilised technique in the field to enhance performance of nanopipettes, and further functionalised with a metal bis thiolate complex, to aid in chemical analysis. The inner channel of the sensing region was exposed with focused ion beam (FIB) milling as a dedicated sample preparation method for nanoscale surface analysis. The sample characterisation involved scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and low-energy energy dispersive x-ray spectroscopy (EDX). The results demonstrate the first steps towards full characterisation of nanopipettes at the nanoscale, notably with access to the inner channel. The methods used here can be applied to gain further understanding of the response of these sensors to complex analytes, and allow for the study of different surface functionalisation at the all-important sensing region. T2 - 2024 Spring Meeting of the European Materials Research Society (E-MRS) CY - Strasbourg, France DA - 27.05.2024 KW - Nanopipettes KW - FIB KW - Surface analysis KW - Surface modification KW - Silanisation PY - 2024 AN - OPUS4-60449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miliūtė, Aistė A1 - Bustamante, Joana A1 - Mieller, Björn A1 - Stawski, Tomasz A1 - George, Janine A1 - Knoop, F. T1 - High-quality zirconium vanadate samples for negative thermal expansion (NTE) analysis N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). The linear thermal expansion coefficient of ZrV2O7 is −7.1×10-6 K-. Therefore, it can be used to create composites with controllable expansion coefficients and prevent destruction by thermal shock. Material characterization, leading to application, requires pure, homogenous samples of high crystallinity via a reliable synthesis route. While there is a selection of described syntheses in the literature, it still needs to be addressed which synthesis route leads to truly pure and homogenous samples. Here, we study the influence of the synthesis methods (solid-state, sol-gel, solvothermal) and their parameters on the sample's purity, crystallinity, and homogeneity. The reproducibility of results and data obtained with scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric analysis (DSC/TGA) were analyzed extensively. The sol-gel method proves superior to the solid-state method and produces higher-quality samples over varying parameters. Sample purity also plays an important role in NTE micro and macro-scale characterizations that explain the impact of porosity versus structural changes. Moreover, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation, temperature-dependent effective harmonic potentials) 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. Khosrovani et al. and Korthuis et al., in a series of diffraction experiments, attributed the thermal contraction of ZrV2O7 to the transverse thermal motion of oxygen atoms in V-O-V linkages. In addition to previous explanations, we hypothesize that local disorder develops in ZrV2O7 crystals during heating. We are working on the experimental ZrV2O7 development and discuss difficulties one might face in the process as well as high-quality sample significance in further investigation. The obtained samples are currently used in the ongoing research of structure analysis and the negative thermal expansion mechanism. T2 - 4th International Symposium on Negative Thermal Expansion and Related Materials (ISNTE-4) CY - Padua, Italy DA - 04.07.2023 KW - NTE KW - Sol-gel KW - Solid-state KW - Ab-initio KW - TDEP PY - 2023 AN - OPUS4-58132 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Pauw, Brian Richard A1 - Laskina, Sofya A1 - Naik, Aakash Ashok A1 - Smales, Glen Jacob A1 - George, Janine A1 - Breßler, Ingo A1 - Benner, Philipp T1 - "Ultima Ratio": Simulating wide-range X-ray scattering and diffraction N2 - We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated patterns can be used to test holistic analysis models, and, since the diffraction intensity is on the same scale as the scattering intensity, may offer a novel pathway for determining the degree of crystallinity. The "Ultima Ratio" strategy is demonstrated on a 64-nm Metal Organic Framework (MOF) particle, calculated from Q < 0.01 1/nm up to Q < 150 1/nm, with a resolution of 0.16 Angstrom. The computations exploit a modified 3D Fast Fourier Transform (3D-FFT), whose modifications enable the transformations of matrices at least up to 8000^3 voxels in size. Multiple of these modified 3D-FFTs are combined to improve the low-Q behaviour. The resulting curve is compared to a wide-range scattering pattern measured on a polydisperse MOF powder. While computationally intensive, the approach is expected to be useful for simulating scattering from a wide range of realistic, complex structures, from (poly-)crystalline particles to hierarchical, multicomponent structures such as viruses and catalysts. KW - X-ray KW - Simulation KW - 3D Fourier Transform KW - High resolution KW - XRD KW - SAXS KW - PDF KW - Total scattering KW - X-ray scattering KW - Metal organic framework KW - Electron density map KW - FFT PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572067 DO - https://doi.org/10.48550/arXiv.2303.13435 VL - Cornell University SP - 1 EP - 12 PB - Ithaca, NY AN - OPUS4-57206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -