TY - JOUR A1 - Arinchtein, A. A1 - Ye, M.-Y. A1 - Yang, Q. A1 - Kreyenschulte, C. A1 - Wagner, Andreas A1 - Frisch, M. A1 - Brückner, A. A1 - Kondratenko, E. A1 - Kraehnert, R. T1 - Dynamics of Reaction-Induced Changes of Model-Type Iron Oxide Phases in the CO2-Fischer-Tropsch-Synthesis JF - ChemCatChem N2 - Iron-based catalysts are employed in CO2-FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2-FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2-FTS atmospheres at 20 bar and 300°C. Up to three distinct phases were observed depending on the timeon-stream (TOS): a sintered maghemite/magnetite phase, a carbidic core-shell structure, and a low-crystalline, needle-type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase. Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed. KW - Nanostructured FeOx films KW - CO2 KW - Scanning Auger Spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549709 DO - https://doi.org/10.1002/cctc.202200240 SN - 1867-3880 VL - 14 IS - 14 SP - 1 EP - 11 PB - Wiley-VCH AN - OPUS4-54970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Falkenhagen, Jana T1 - Combined impact of UV radiation and nitric acid on high‐density polyethylene containers as a laboratory test JF - Packaging Technology and Science N2 - In a laboratory test, transparent high‐density polyethylene (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 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. This is caused by the decomposition of nitric acid into nitrous gases by UV radiation, which is also observed at lower concentrations (28 wt‐%). After 6 days of laboratory exposure, this is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. The gradual increase in oxidative damage shows the reproducibility of the test. KW - Molecular mass distribution KW - High-density polyethylene KW - Nitric acid KW - UV radiation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550141 DO - https://doi.org/10.1002/pts.2673 SN - 0894-3214 SP - 1 EP - 7 PB - John Wiley & Sons Ltd AN - OPUS4-55014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Belenguer, A. A1 - Lampronti, G. A1 - Michalchuk, Adam A1 - Emmerling, Franziska A1 - Sanders, J. T1 - Quantitative reversible one pot interconversion of three crystalline polymorphs by ball mill grinding JF - Crystengcomm N2 - We demonstrate here using a disulfide system the first example of reversible, selective, and quantitative transformation between three crystalline polymorphs by ball mill grinding. This includes the discovery of a previously unknown polymorph. Each polymorph is reproducibly obtained under well-defined neat or liquid-assisted grinding conditions, revealing subtle control over the apparent thermodynamic stability. We discovered that the presence of a contaminant as low as 1.5% mol mol−1 acting as a template is required to enable all these three polymorph transformations. The relative stabilities of the polymorphs are determined by the sizes of the nanocrystals produced under different conditions and by surface interactions with small amounts of added solvent. For the first time, we show evidence that each of the three polymorphs is obtained with a unique and reproducible crystalline size. This mechanochemical approach gives access to bulk quantities of metastable polymorphs that are inaccessible through recrystallisation. KW - Mechanochemistry KW - Polymorph KW - XRD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549934 DO - https://doi.org/10.1039/D2CE00393G SP - 1 EP - 7 PB - Royal Society of Chemistry AN - OPUS4-54993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Margreiter, R. A1 - Baumann, J. A1 - Mantouvalou, I. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Strub, E. T1 - Investigations on fire-gilding JF - Archaeometry N2 - Fire-gilding is a historic technique for the application of golden layers on a number of different base materials utilizing a gold amalgam. This technique leaves a significant amount of Hg in the golden layer, giving archeometrists a reliable indicator to identify firegildings. Recent findings on presumably fire-gilded objects have shown in several cases significantly lower Hg content than previously studied objects. This prompted a synchrotron-based X-ray fluorescence investigation into the Hg distribution along the material–gilding interface, as well as a series of measurements regarding the Hg content development in fire-gilded samples during artificial aging. This work presents findings on laboratory-prepared fire-gildings, indicating an Hg enrichment at the interface of firegilded silver samples. Notably, such an enrichment is missing in fire-gilded copper samples. Further, it is confirmed that fire-gilded layers typically do not undercut an Hg bulk content of 5%. In this light, it seems improbable that ancient samples that contain <5% Hg are fire-gilded. The results presented in this study might lead to a non-destructive method to identify the Hg enrichment at the interface. This might be obtained by a combination of different non-destructive measurements and might also work unambiguously in samples in which the gold top layer is altered. KW - BAMline KW - X-Ray Fluorescence KW - Gilding KW - Depth profile KW - Archaeometry PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552885 DO - https://doi.org/10.1111/arcm.12797 SN - 0003-813X SP - 1 EP - 14 PB - Wiley online library AN - OPUS4-55288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Schmidt, Alexandra A1 - Rasmussen, K. A1 - Rauscher, H. T1 - Counting Small Particles in Electron Microscopy Images — Proposal for Rules and Their Application in Practice JF - Nanomaterials N2 - Electron microscopy (EM) is the gold standard for the characterisation of the morphology (size and shape) of nanoparticles. Visual observation of objects under examination is always a necessary first step in the characterisation process. Several questions arise when undertaking to identify and count particles to measure their size and shape distribution. In addition to challenges with the dispersion and identification of the particles, more than one protocol for counting particles is in use. This paper focuses on precise rules for the counting of particles in EM micrographs, as this influences the measurement accuracy of the number of particles, thus implicitly affecting the size values of the counted particles. We review and compare four different, commonly used methods for counting, which we then apply in case studies. The impact of the selected counting rule on the obtained final particle size distribution is highlighted. One main aim of this analysis is to support the application of a specific, well-defined counting approach in accordance with regulatory requirements to contribute to achieving more reliable and reproducible results. It is also useful for the new harmonised measurement procedures for determining the particle size and particle size distribution of nanomaterials. KW - Nano KW - Particle size distribution KW - Nanoparticle KW - Nanomaterial KW - OECD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551891 DO - https://doi.org/10.3390/nano12132238 SN - 2079-4991 VL - 12 IS - 13 SP - 2238 PB - MDPI CY - Basel AN - OPUS4-55189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kittner, Maria A1 - Kerndorff, A. A1 - Ricking, M. A1 - Bednarz, M. A1 - Obermaier, N. A1 - Lukas, M. A1 - Asenova, M. A1 - Bordós, G. A1 - Eisentraut, Paul A1 - Hohenblum, P. A1 - Hudcova, H. A1 - Humer, F. A1 - István, T. G. A1 - Kirchner, M. A1 - Marushevska, O. A1 - Nemejcová, D. A1 - Oswald, P. A1 - Paunovic, M. A1 - Sengl, M. A1 - Slobodnik, J. A1 - Spanowsky, K. A1 - Tudorache, M. A1 - Wagensonner, H. A1 - Liska, I. A1 - Braun, U. A1 - Bannick, C. G. T1 - Microplastics in the Danube River Basin: A First Comprehensive Screening with a Harmonized Analytical Approach JF - ACS ES&T Water N2 - In this study, carried out within the Joint Danube Survey 4, a comprehensive microplastic screening in the water column within a large European river basin from its source to estuary, including major tributaries, was realized. The objective was to develop principles of a systematic and practicable microplastic monitoring strategy using sedimentation boxes for collection of suspended particulate matter followed by its subsequent analysis using thermal extraction desorption-gas chromatography/mass spectrometry. In total, 18 sampling sites in the Danube River Basin were investigated. The obtained suspended particulate matter samples were subdivided into the fractions of >100 μm and <100 μm and subsequently analyzed for microplastic mass contents. The results showed that microplastics were detected in all samples, with polyethylene being the predominant polymer with maximum contents of 22.24 μg/mg, 3.23 μg/mg for polystyrene, 1.03 μg/mg for styrene-butadiene-rubber, and 0.45 μg/mg for polypropylene. Further, polymers such as different sorts of polyester, polyacrylates, polylactide, and natural rubber were not detected or below the detection limit. Additional investigations on possible interference of polyethylene signals by algae-derived fatty acids were assessed. In the context of targeted monitoring, repeated measurements provide more certainty in the interpretation of the results for the individual sites. Nevertheless, it can be stated that the chosen approach using an integrative sampling and determination of total plastic content proved to be successful. KW - Thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), monitoring KW - Microplastics KW - River KW - Suspended particulate matter (SPM) KW - Sedimentation box (SB) PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551444 DO - https://doi.org/10.1021/acsestwater.1c00439 VL - 2 IS - 7 SP - 1174 EP - 1181 PB - ACS Publications AN - OPUS4-55144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - George, Janine A1 - Petretto, G. A1 - Naik, Aakash Ashok A1 - Esters, M. A1 - Jackson, A. J. A1 - Nelson, R. A1 - Dronskowski, R. A1 - Rignanese, G.-M. A1 - Hautier, G. T1 - Automated bonding analysis with crystal orbital Hamilton populuations JF - ChemPlusChem N2 - Automated bonding analysis software has been developed based on Crystal Orbital Hamilton Populations to facilitate high-throughput bonding analysis and machine-learning of bonding features. This work presents the software and discusses its applications to simple and complex materials such as GaN, NaCl, the oxynitrides XTaO2N (X=Ca, Ba, Sr) and Yb14Mn1Sb11. KW - Chemical bonds KW - Automation KW - High-throughput PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551641 DO - https://doi.org/10.1002/cplu.202200123 SN - 2192-6506 SP - 1 EP - 11 PB - Wiley-VCH CY - Weinheim AN - OPUS4-55164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films JF - Advanced optical technologies N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing. We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP). KW - Electrochemical catalysts KW - Mixed metal oxide KW - Multi-sample analysis KW - Spectroscopic ellipsometry KW - Thin mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026 DO - https://doi.org/10.1515/aot-2022-0007 SN - 2192-8584 SN - 2192-8576 VL - 11 IS - 3-4 (Topical issue: Ellipsometry) SP - 137 EP - 147 PB - De Gruyter CY - Berlin AN - OPUS4-55102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Das, Chayanika A1 - Kastania, Eleni A1 - Witt, Julia A1 - Özcan Sandikcioglu, Özlem T1 - Corrosion protection properties of poly(4-vinyl pyridine) containing multilayer polymeric coatings on magnesium alloy AZ31 JF - Materials and Corrosion N2 - The aim of this study is to develop polymeric thin films for corrosion protection of magnesium alloy AZ31. As polymer matrix, poly(4-vinyl pyridine) (P4VP) is selected due to its semiconducting properties and protonic conductivity. Polyacrylic acid is tested as crosslinking layers to improve interfacial adhesion. The macroscopic corrosion properties of the multilayer coatings are investigated by means of electrochemical methods, such as linear sweep voltammetry and electrochemical impedance spectroscopy (EIS), in corrosive media simulating technical and biomedical applications. It is demonstrated that thin multilayer coatings can suppress the corrosion rates of magnesium alloys. To our best knowledge, this is the first demonstration of the use of P4VP as a conducting polymer film with protonic conductivity for corrosion protection of magnesium alloys. KW - Multilayercoatings KW - AZ31 KW - Corrosion protection KW - Intrinsically conducting polymers KW - Magnesium alloys PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551799 DO - https://doi.org/10.1002/maco.202112708 SN - 0947-5117 VL - 73 IS - 3 SP - 427 EP - 435 PB - Wiley VHC-Verlag AN - OPUS4-55179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Accorsi, M. A1 - Tiemann, M. A1 - Wehrhan, L. A1 - Finn, Lauren M. A1 - Cruz, R. A1 - Rautenberg, Max A1 - Emmerling, Franziska A1 - Heberle, J. A1 - Keller, B. G. A1 - Rademann, J. T1 - Pentafluorophosphato-Phenylalanines: Amphiphilic Phosphotyrosine Mimetics Displaying Fluorine-Specific Protein Interactions JF - Angewandte Chemie International Edition N2 - Phosphotyrosine residues are essential functional switches in health and disease. Thus, phosphotyrosine biomimetics are crucial for the development of chemical tools and drug molecules. We report here the discovery and investigation of pentafluorophosphato amino acids as novel phosphotyrosine biomimetics. A mild acidic pentafluorination protocol was developed and two PF5-amino acids were prepared and employed in peptide synthesis. Their structures, reactivities, and fluorine-specific interactions were studied by NMR and IR spectroscopy, X-ray diffraction, and in bioactivity assays. The mono-anionic PF5 motif displayed an amphiphilic character binding to hydrophobic surfaces, to water molecules, and to protein-binding sites, exploiting charge and H−F-bonding interactions. The novel motifs bind 25- to 30-fold stronger to the phosphotyrosine binding site of the protein tyrosine phosphatase PTP1B than the best current biomimetics, as rationalized by computational methods, including molecular dynamics simulations. KW - Chemical Biology KW - Drug Development KW - Pentafluorophosphates KW - Phosphotyrosine Biomimetics KW - Protein Tyrosine Phosphatases PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549984 DO - https://doi.org/10.1002/anie.202203579 SN - 1433-7851 VL - 134 IS - 25 SP - 1 EP - 6 PB - Wiley-VCH GmbH AN - OPUS4-54998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Porta-Velilla, L. A1 - Turan, N. A1 - Cubero, Á. A1 - Shao, W. A1 - Li, H. A1 - de la Fuente, G.F. A1 - Martínez, E. A1 - Larrea, Á. A1 - Castro, M. A1 - Koralay, H. A1 - Çavdar, Ş. A1 - Bonse, Jörn A1 - Angurel, L.A. T1 - Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses JF - Nanomaterials N2 - Nickel tungsten alloy tapes (Ni—5 at% W, 10 mm wide, 80 µm thick, biaxially textured) used in second-generation high temperature superconductor (2G-HTS) technology were laser-processed in air with ultraviolet ps-laser pulses (355 nm wavelength, 300 ps pulse duration, 250–800 kHz pulse repetition frequency). By employing optimized surface scan-processing strategies, various laser-generated periodic surface structures were generated on the tapes. Particularly, distinct surface microstructures and nanostructures were formed. These included sub-wavelength-sized highly-regular hexagonally-arranged nano-protrusions, wavelength-sized line-grating-like laser-induced periodic surface structures (LIPSS, ripples), and larger irregular pyramidal microstructures. The induced surface morphology was characterized in depth by electron-based techniques, including scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), cross-sectional transmission electron microscopy (STEM/TEM) and energy dispersive X-ray spectrometry (EDS). The in-depth EBSD crystallographic analyses indicated a significant impact of the material initial grain orientation on the type of surface nanostructure and microstructure formed upon laser irradiation. Special emphasis was laid on high-resolution material analysis of the hexagonally-arranged nano-protrusions. Their formation mechanism is discussed on the basis of the interplay between electromagnetic scattering effects followed by hydrodynamic matter re-organization after the laser exposure. The temperature stability of the hexagonally-arranged nano-protrusion was explored in post-irradiation thermal annealing experiments, in order to qualify their suitability in 2G-HTS fabrication technology with initial steps deposition temperatures in the range of 773–873 K. KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser processing KW - Hexagonally-arranged nano-protrusions KW - Second-generation high temperature superconductor technology KW - Electron microscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552551 DO - https://doi.org/10.3390/nano12142380 SN - 2079-4991 VL - 12 IS - 14 SP - 1 EP - 23 PB - MDPI CY - Basel, Switzerland AN - OPUS4-55255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Linberg, Kevin A1 - Röder, Bettina A1 - Al-Sabbagh, Dominik A1 - Emmerling, Franziska A1 - Michalchuk, Adam T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling JF - Faraday Discussions N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point. Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools. KW - Mechanochemistry KW - Polymorphism KW - TRIS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564728 DO - https://doi.org/10.1039/d2fd00115b SP - 1 EP - 16 PB - Royal Society of Chemistry AN - OPUS4-56472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lifka, S. A1 - Harsányi, K. A1 - Baumgartner, E. A1 - Pichler, L. A1 - Baiko, D. A1 - Wasmuth, Karsten A1 - Heitz, J. A1 - Meyer, M. A1 - Joel, A.-C. A1 - Bonse, Jörn A1 - Baumgartner, W. ED - Mail, M. T1 - Laser-processed antiadhesive bionic combs for handling nanofibers inspired by nanostructures on the legs of cribellate spiders JF - Beilstein Journal of Nanotechnology N2 - Nanofibers are drawing the attention of engineers and scientists because their large surface-to-volume ratio is favorable for applications in medicine, filter technology, textile industry, lithium-air batteries, and optical sensors. However, when transferring nanofibers to a technical product in the form of a random network of fibers, referred to as nonwoven fabric, the stickiness of the freshly produced and thus fragile nanofiber nonwoven remains a problem. This is mainly because nanofibers strongly adhere to any surface because of van der Waals forces. In nature, there are animals that are actually able to efficiently produce, process, and handle nanofibers, namely cribellate spiders. For that, the spiders use the calamistrum, a comb-like structure of modified setae on the metatarsus of the hindmost (fourth) legs, to which the 10–30 nm thick silk nanofibers do not stick due to a special fingerprint-like surface nanostructure. In this work, we present a theoretical model of the interaction of linear nanofibers with a sinusoidally corrugated surface. This model allows for a prediction of the adhesive interaction and, thus, the design of a suitable surface structure to prevent sticking of an artificially nonwoven of nanofibers. According to the theoretical prediction, a technical analogon of the nanoripples was produced by ultrashort pulse laser processing on different technically relevant metal surfaces in the form of so-called laser-induced periodic surface structures (LIPSS). Subsequently, by means of a newly established peel-off test, the adhesion of an electrospun polyamide fiber-based nonwoven was quantified on such LIPSS-covered aluminium alloy, steel, and titanium alloy samples, as well as on polished (flat) control samples as reference and, additionally, on samples with randomly rough surfaces. The latter revealed that the adhesion of electrospun nanofiber nonwoven is significantly lowered on the nanostructured surfaces compared with the polished surfaces. KW - Laser-induced periodic surface structures (LIPSS) KW - Cribellate spiders KW - Calamistrum KW - Electrospinning KW - Nanofibers PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561799 DO - https://doi.org/10.3762/bjnano.13.105 SN - 2190-4286 VL - 13 SP - 1268 EP - 1283 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-56179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Loges, A. A1 - Scholz, G. A1 - Amadeu de Sosa, Nader A1 - Jingjing, S. A1 - Emmerling, Franziska A1 - John, T. A1 - Paulus, B. A1 - Braun, T. T1 - Studies on the local structure of the F/OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy JF - European journal of mineralogy N2 - he mutual influence of F and OH groups in neighboring sites in topaz (Al2SiO4(F,OH)2) was investigated using magic angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The splitting of 19F and 1H NMR signals, as well as the OH Raman band, provides evidence for hydrogen bond formation within the crystal structure. Depending on whether a given OH group has another OH group or fluoride as its neighbor, two different hydrogen bond constellations may form: either OH···O···HO or F···H···O. The proton accepting oxygen was determined to be part of the SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR data between an OH-bearing and an OH-free topaz sample confirms that the 19F signal at −130 ppm stems from F− ions that take part in H···F bonds with a distance of ∼ 2.4 Å, whereas the main signal at −135 ppm belongs to fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at 3644 cm−1 stems from OH groups neighboring other OH groups, whereas the sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors, which are affected by H···F bridging. The integrated intensities of these two sub-bands do not conform to the expected ratios based on probabilistic calculations from the total OH concentration. This can be explained by a difference in the polarizability of the OH bond between the different hydrogen bond constellations or partial order or unmixing of F and OH, or a combination of both. This has implications for the quantitative interpretation of Raman data on OH bonds in general and their potential use as a probe for structural (dis-)order. No indication of tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting that the investigated samples likely have nearly ideal Al/Si ratios, making them potentially useful as high-density electron microprobe reference materials for Al and Si, as well as for F. KW - Topas KW - NMR KW - XRD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561863 DO - https://doi.org/10.5194/ejm-34-507-2022 SN - 1617-4011 VL - 34 IS - 5 SP - 507 EP - 521 PB - Copernicus Publications CY - Göttingen AN - OPUS4-56186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Hoch, C. T1 - Laudatio Prof. Dr.-Ing. Caroline Röhr JF - Zeitschrift für anorganische und allgemeine Chemie N2 - It is a laudatio on the ocations of Prof. Dr.-Ing. Caroline Röhrs 60th birthday. KW - Metal-oxides PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561877 DO - https://doi.org/10.1002/zaac.202200159 SN - 0044-2313 VL - 648 IS - 10 SP - 1 EP - 2 PB - John Wiley & Sons, Ltd AN - OPUS4-56187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Iro, M. A1 - Ingerle, D. A1 - Radtke, Martin A1 - de Oliveira Guilherme Buzanich, Ana A1 - Kregsamer, P. A1 - Streli, C. T1 - Investigation of polycapillary half lenses for quantitative confocal micro-X-ray fluorescence analysis JF - Journal of synchrotron radiation N2 - The use of polycapillary optics in confocal micro-X-ray fluorescence analysis (CMXRF) enables the destruction-free 3D investigation of the elemental composition of samples. The energy-dependent transmission properties, concerning intensity and spatial beam propagation of three polycapillary half lenses, which are vital for the quantitative interpretation of such CMXRF measurements, are investigated in a monochromatic confocal laboratory setup at the Atominstitut of TU Wien, and a synchrotron setup on the BAMline beamline at the BESSY II Synchrotron, Helmholtz-Zentrum-Berlin. The empirically established results, concerning the intensity of the transmitted beam, are compared with theoretical values calculated with the polycap software package and a newly presented analytical model for the transmission function. The resulting form of the newly modelled energy-dependent transmission function is shown to be in good agreement with Monte Carlo simulated results for the complete energy regime, as well as the empirically established results for the energy regime between 6 keV and 20 keV. An analysis of possible fabrication errors was conducted via pinhole scans showing only minor fabrication errors in two of the investigated polycapillary optics. The energy-dependent focal spot size of the primary polycapillary was investigated in the laboratory via the channel-wise evaluation of knife-edge scans. Experimental results are compared with data given by the manufacturer as well as geometric estimations for the minimal focal spot size. Again, the resulting measurement points show a trend in agreement with geometrically estimated results and manufacturer data. KW - BAMline KW - Synchrotron KW - Capillary KW - confocal PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562430 DO - https://doi.org/10.1107/S1600577522009699 SN - 1600-5775 VL - 29 SP - 1376 EP - 1384 PB - International Union of Crystallography CY - Chester AN - OPUS4-56243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de O. Primo, J. A1 - Horsth, D.F. A1 - de S. Correa, J. A1 - Das, A. A1 - Bittencourt, C. A1 - Umek, P. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Yusenko, Kirill A1 - Zanetta, C. A1 - Anaissi, F.J. T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water JF - Nanomaterials N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis- infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency. KW - Synchrotron KW - BAMline PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440 DO - https://doi.org/10.3390/nano12101764 SN - 2079-4991 VL - 12 IS - 10 SP - 1 EP - 18 PB - MDPI CY - Basel AN - OPUS4-56244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehri, S. A1 - Kolmangadi, Mohamed Aejaz A1 - Dyre, J.C. A1 - Ingebrigtsen, T.S. T1 - Lines of invariant physics in the isotropic phase of the discotic Gay-Berne model JF - Journal of Non-Crystalline Solids: X N2 - The Gay-Berne model is studied numerically with a choice of parameters allowing for the formation of a discotic liquid crystal at low temperatures. We show that the model has strong virial potential-energy correlations in the isotropic phase at high temperatures, i.e., it obeys the criterion for the existence of isomorphs, which are curves of approximately invariant structure and dynamics. These properties are demonstrated to be approximately invariant in reduced units along the isomorph studied. The isomorph is described well by the constant density-scaling exponent 11.5, a number that is significantly larger than the density-scaling exponents of various Lennard-Jones models that are always below 6. KW - Liquid Crystal KW - Molecular Dynamics PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547611 DO - https://doi.org/10.1016/j.nocx.2022.100085 VL - 14 SP - 1 EP - 7 PB - Elsevier B.V. AN - OPUS4-54761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bugel, S. A1 - Hahnel, M. A1 - Kunde, T. A1 - de Sousa Amadeu, Nadar A1 - Sun, Y. A1 - Spieß, A. A1 - Beglau, T. H. Y. A1 - Janiak, C. A1 - Schmidt, B. M. T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation JF - Materials N2 - A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,4′-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM. KW - MOF KW - Filter PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547632 DO - https://doi.org/10.3390/ma15082807 SN - 1996-1944 VL - 15 IS - 8 SP - 1 EP - 18 PB - MDPI AN - OPUS4-54763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zänker, Steffen A1 - Scholz, G. A1 - Marquardt, Julien A1 - Emmerling, Franziska T1 - Structural changes in Ba-compounds of different hardness induced by high-energy ball milling – evidenced by 137Ba NMR and X-ray powder diffraction JF - Zeitschrift für anorganische und allgemeine Chemie N2 - Changes in the global bulk and local structures, of three different barium compounds (BaZrO3, BaF2, and BaFCl),were induced by mechanical milling and followed using X-ray powder diffraction (PXRD), subsequent microstructure analysis, and 137Ba solid state NMR spectroscopy. Harder materials like BaZrO3 experience significantly higher structural changes upon milling than softer materials like BaF2. Moreover, soft materials with layered structures, like BaFCl, show a pronounced structural change during the milling process. By combining PXRD and solid state NMR, detailed information on the changes to the global and local structures were obtained, which are of interest for mechanochemical synthesis, mechanically treated catalysts or ionic conductors. KW - Mechanochemistry KW - X-ray diffraction KW - Solid state NMR PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547397 DO - https://doi.org/10.1002/zaac.202200026 SN - 0044-2313 VL - 648 IS - 10 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernges, T. A1 - Hanus, R. A1 - Wankmiller, B. A1 - Imasato, K. A1 - Lin, S. A1 - Ghidiu, M. A1 - Gerlitz, M. A1 - Peterlechner, M. A1 - Graham, S. A1 - Hautier, G. A1 - Pei, Y. A1 - Hansen, M. R. A1 - Wilde, G. A1 - Snyder, G. J. A1 - George, Janine A1 - Agne, M T. A1 - Zeier, W. G. T1 - Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity JF - Advanced Energy Materials N2 - Next-generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two-channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non-propagating diffuson-like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson-mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson-mediated transport. Bridging the fields of solid-state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so-called Meyer-Neldel behavior in ionic conductors to phonon occupations. KW - Diffusons KW - DFT KW - Phonons KW - Thermoelectrics PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547140 DO - https://doi.org/10.1002/aenm.202200717 SN - 1614-6832 VL - 12 IS - 22 SP - 1 EP - 13 PB - Wiley VHC-Verlag AN - OPUS4-54714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chambers, M. S. A1 - Hunter, R. D. A1 - Hollamby, M. J. A1 - Pauw, Brian Richard A1 - Smith, A. J. A1 - Snow, T. A1 - Danks, A. E. A1 - Schnepp, Z. T1 - In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C JF - Inorganic Chemistry N2 - Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows: Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles. KW - Small-angle X-ray Scattering KW - SAXS KW - Diffraction KW - XRD KW - Scattering KW - Sol-gel KW - Iron nitride KW - Nanoparticles KW - Iron carbide KW - Catalyst KW - In-situ KW - Ex-situ KW - Synthesis KW - Synchrotron PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548226 DO - https://doi.org/10.1021/acs.inorgchem.1c03442 VL - 61 IS - 18 SP - 6742 EP - 6749 PB - ACS Publications CY - Washington AN - OPUS4-54822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mazzeo, P. P. A1 - Prencipe, M. A1 - Feiler, Torvid A1 - Emmerling, Franziska A1 - Bacchi, A. T1 - On the mechanism of cocrystal mechanochemical reaction via low melting eutectic: A time-resolved in situ monitoring investigation JF - Crystal growth and design N2 - Mechanochemistry has become a sustainable and attractive cost-effective synthetic technique, largely used within the frame of crystal engineering. Cocrystals, namely, crystalline compounds made of different chemical entities within the same crystal structure, are typically synthesized in bulk via mechanochemistry; however, whereas the macroscopic aspects of grinding are becoming clear, the fundamental principles that underlie mechanochemical cocrystallization at the microscopic level remain poorly understood. Time-resolved in situ (TRIS) monitoring approaches have opened the door to exceptional detail regarding mechanochemical reactions. We here report a clear example of cocrystallization between two solid coformers that proceeds through the formation of a metastable low melting binary eutectic phase. The overall cocrystallization process has been monitored by time-resolved in situ (TRIS) synchrotron X-ray powder diffraction with a customized ball milling setup, currently available at μ Spot beamline at BESSY-II, Helmholtz-Zentrum Berlin. The binary system and the low melting eutectic phase were further characterized via DSC, HSM, and VT-XRPD. KW - Mechanochemistry KW - In situ KW - Cocrystal PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552977 DO - https://doi.org/10.1021/acs.cgd.2c00262 SN - 1528-7505 VL - 22 IS - 7 SP - 4260 EP - 4267 PB - ACS Publ. CY - Washington, DC AN - OPUS4-55297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Structuring of thin films by ultrashort laser pulses JF - Applied physics A N2 - Modern life and global communication would not be possible without technologically tailored thin films; they are omnipresent in daily life applications. In most cases, the films are deposited entirely at the carrying substrates in a specific processing step of the device or sample. In some cases, however, removal or modification must be performed locally, i.e., site-controlled and material selective through an additional laser processing step. For that ultrashort laser pulses with durations in the femtosecond and picosecond range can provide unique advantages and capabilities in industrially scalable schemes. This article reviews the current state of the research and corresponding industrial transfer related to the structuring of thin films by ultrashort pulsed lasers. It focuses on the pertinent historic developments, reveals the relevant physical and chemical effects, explores the ultimate limits, and discusses selected industrial and scientific applications. KW - Thin films KW - Laser processing KW - Ultrashort lasers KW - Laser damage KW - Femtosecond laser ablation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565732 DO - https://doi.org/10.1007/s00339-022-06229-x SN - 0947-8396 SN - 1432-0630 VL - 129 IS - 1 SP - 1 EP - 38 PB - Springer CY - Berlin AN - OPUS4-56573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Meyer, A. T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals JF - Macromolecular Chemistry and Physics N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts(2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and 2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL) are performed at 140 °C in bulk. Small amounts (4 vol%) of chlorobenzene or other solvents are added to facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hmmax, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data. KW - Polylactide KW - MALDI-TOF MS KW - Ring-expansion polymerization KW - Crystals PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565038 DO - https://doi.org/10.1002/macp.202200385 SN - 1022-1352 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-56503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kohlbrecher, J. A1 - Breßler, Ingo T1 - Updates in SASfit for fitting analytical expressions and numerical models to small-angle scattering patterns JF - Journal of applied crystallography N2 - Small-angle scattering is an increasingly common method for characterizing particle ensembles in a wide variety of sample types and for diverse areas of application. SASfit has been one of the most comprehensive and flexible curve-fitting programs for decades, with many specialized tools for various fields. Here, a selection of enhancements and additions to the SASfit program are presented that may be of great benefit to interested and advanced users alike: (a) further development of the technical basis of the program, such as new numerical algorithms currently in use, a continuous integration practice for automated building and packaging of the software, and upgrades on the plug-in system for easier adoption by third-party developers; (b) a selection of new form factors for anisotropic scattering patterns and updates to existing form factors to account for multiple scattering effects; (c) a new type of a very flexible distribution called metalog [Keelin (2016). Decis. Anal. 13, 243–277], and regularization techniques such as the expectation-maximization method [Dempster et al. (1977). J. R. Stat. Soc. Ser. B (Methodological), 39, 1–22; Richardson (1972) J. Opt. Soc. Am. 62, 55; Lucy (1974). Astron. J. 79, 745; Lucy (1994). Astron. Astrophys. 289, 983–994], which is compared with fits of analytical size distributions via the non-linear least-squares method; and (d) new structure factors, especially for ordered nano- and meso-scaled material systems, as well as the Ornstein–Zernike solver for numerical determination of particle interactions and the resulting structure factor when no analytical solution is available, with the aim of incorporating its effects into the small-angle scattering intensity model used for fitting with SASfit. KW - Small-angle scattering KW - Numerical models KW - Structure factors KW - Regularization KW - SAXS KW - SANS PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565069 DO - https://doi.org/10.1107/S1600576722009037 SN - 0021-8898 SN - 1600-5767 VL - 55 IS - 6 SP - 1677 EP - 1688 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-56506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Linberg, Kevin A1 - Emmerling, Franziska A1 - Michalchuk, Adam T1 - Unintended Rate Enhancement in Mechanochemical Kinetics by Using Poly(methyl methacrylate) Jars JF - Crystal Growth & Design N2 - Time-resolved in situ (TRIS) X-ray diffraction has changed how mechanochemical transformations are studied but requires the use of X-ray transparent jars often made from poly(methyl methacrylate) (PMMA). However, using PMMA jars can alter the apparent kinetics of mechanochemical polymorphism by an order of magnitude, questioning the interpretability of established TRIS methods. Our results suggest that rate enhancement in PMMA jars may not be dominated by chemical effects of the polymer, but rather a result of different equilibrium temperatures within the jar. These features must be better understood before control over mechanochemical reactions can be achieved. KW - Mechanochemistry KW - Organic compounds KW - Polymers KW - Materials PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565276 DO - https://doi.org/10.1021/acs.cgd.2c01227 SN - 1528-7483 SP - 1 EP - 5 PB - ACS Publications AN - OPUS4-56527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ravi, J. A1 - Feiler, Torvid A1 - Mondal, A. A1 - Michalchuk, Adam A1 - Reddy, C. M. A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska A1 - Chandrasekar, R. T1 - Plastically bendable organic crystals for monolithic and hybrid micro-optical circuits JF - Advanced optical materials N2 - Fluorescent plastically bendable crystals are a promising alternative to silicon-based materials for fabricating photonic integrated circuits, owing to their optical attributes and mechanical compliance. Mechanically bendable plastic organic crystals are rare. Their formation requires anisotropic intermolecular interactions and slip planes in the crystal lattice. This work presents three fluorescent plastically bendable crystalline materials namely, 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-chlorophenol (SB1), 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-bromophenol (SB2), and 2-((E)-(6-Bromopyridin-2-ylimino)methyl)-4-bromophenol (SB3) molecules. The crystal plasticity in response to mechanical stress facilitates the fabrication of various monolithic and hybrid (with a tip-to-tip coupling) photonic circuits using mechanical micromanipulation with an atomic force microscope cantilever tip. These plastically bendable crystals act as active (self-guiding of fluorescence) and passive waveguides both in straight and extremely bent (U-, J-, and O-shaped) geometries. These microcircuits use active and passive waveguiding principles and reabsorbance and energy-transfer mechanisms for their operation, allowing input-selective and direction-specific signal transduction. KW - Flexible crystals KW - Flexible waveguide PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565302 DO - https://doi.org/10.1002/adom.202201518 SN - 2195-1071 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-56530 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Katrin A1 - Schmitt Rahner, M. A1 - Stolzenberg, U. A1 - Kraft, Sebastian A1 - Bonse, Jörn A1 - Feist, C. A1 - Albrecht, D. A1 - Pullner, B. A1 - Krüger, Jörg T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing JF - Materials N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2. KW - Ultrashort pulsed laser KW - X-ray emission KW - X-ray spectrum KW - X-ray energies KW - Radiation protection PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176 DO - https://doi.org/10.3390/ma15248996 VL - 15 IS - 24 SP - 1 EP - 17 PB - MDPI AN - OPUS4-56617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - Synthesis of polylactides by means of tin catalysts JF - Polymer Chemistry N2 - This article reviews the usefulness of tin(II) and tin(IV) salts and compounds as catalysts for the polymerization of lactides. The text is subdivided into nine parts mainly reflecting different polymerization strategies, such as ring-opening polymerization (ROP), ring-expansion polymerization (REP), ROP combined with simultaneous polycondensation (ROPPOC), various catalysts with unknown polymerization mechanisms, and polycondensation of lactic acid. Since the toxicity of tin salts and compounds is a matter of concern and frequently mentioned in numerous publications, the first section deals with facts instead of myths about the toxicity of tin salts and compounds. KW - Polylactide KW - MALDI-TOF MS KW - Tin catalysts PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545050 DO - https://doi.org/10.1039/d2py00092j SP - 1 EP - 30 PB - Royal Society for Chemistry AN - OPUS4-54505 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 - Tyagi, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Low frequency vibrations and diffusion in disordered polymers bearing an intrinsic microporosity as revealed by neutron scattering JF - Crystals N2 - The microscopic diffusion and the low frequency density of states (VDOS) of PIM-EATB(CH3) are investigated by inelastic and quasi-elastic neutron scattering where also the demethylated counterpart of PIM-EA-TB(H2) is considered. These intrinsic microporous polymers are characterized by large BET surface area values of several hundred m2/g and pore sizes between 0.5 and 2 nm. Detailed comparison is made to the archetype of polymers of intrinsic microporosity, PIM-1, and polynorbornenes also bearing a microporosity. Due to the wavelength of neutrons, the diffusion and vibrations can be addressed on microscopic length and time scales. From the inelastic neutron scattering experiments the low frequency density of states (VDOS) is estimated which shows excess contributions to the Debye-type VDOS known as Boson peak. It was found that the maximum frequency of the Boson peak decreases with increasing microporosity characterized by the BET surface area. However, besides the BET surface area, additional factors such as the backbone stiffness govern the maximum frequency of the Boson peak. Further the mean squared displacement related to microscopic motions was estimated from elastic fixed window scans. At temperatures above 175 K, the mean squared displacement PIM-EA-TB(CH3) is higher than that for the demethylated counterpart PIM-EA-TB(H2). The additional contribution found for PIM-EATB(CH3) is ascribed to the rotation of the methyl group in this polymer because the only difference between the two structures is that PIM-EA-TB(CH3) has methyl groups where PIM-EA-TB(H2) has none. A detailed comparison of the molecular dynamics is also made to that of PIM-1 and the microporous polynorbornene PTCNSi1. The manuscript focuses on the importance of vibrations and the localized molecular mobility characterized by the microscopic diffusion on the gas Transport in polymeric separation membranes. In the frame of the random gate model localized fluctuations can open or close bottlenecks between pores to enable the diffusion of gas molecules. KW - Polymer of intrisic microporosity KW - Neutron scattering KW - Boson peak KW - Methyl group rotation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538490 DO - https://doi.org/10.3390/cryst11121482 VL - 11 IS - 12 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-53849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Musl, O. A1 - Sulaeva, I. A1 - Sumerskii, I. A1 - Mahler, A.K. A1 - Rosenau, T. A1 - Falkenhagen, Jana A1 - Potthast, A. T1 - Mapping of the Hydrophobic Composition of Lignosulfonates JF - ACS Sustainable Chemistry&Engineering N2 - Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in molar mass (molar mass distribution-MMD) and in functionalities (functionality-type distribution - FTD), which crucially affect their material usage. In terms of FTD, state-of-the-art Lignin analytics still rely mainly on the determination of functional group contents, which are statistical averages with limited explanatory power. In contrast, our online hydrophobic interaction chromatography−size-exclusion chromatography 2D-LC approach combines the determination of both MMD and FTD in a single measurement to provide a comprehensive picture of the characteristic composition of industrial lignosulfonates information hitherto inaccessible by state-of-the-art lignin analytics. In this way, the complex inter - relationships between these two important structural parameters can be studied in an unprecedented manner. In this study, we reveal the considerable differences in terms of hydrophobic composition and its dispersity present in a range of different industrial lignosulfonates - data desperately needed in tailoring and refining of lignosulfonate composition for material usage. KW - Lignosulfonates KW - Amphiphilicity KW - Hydrophobic interaction chromatography KW - Two-dimensional chromatography (2D-LC) KW - Charge-to-size-ratio PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538612 DO - https://doi.org/10.1021/acssuschemeng.1c06469 VL - 9 IS - 49 SP - 16786 EP - 16795 PB - ASC Publications AN - OPUS4-53861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Getenet, M. A1 - Garcia-Ruiz, J. M. A1 - Otálora, F. A1 - Emmerling, Franziska A1 - Al-Sabbagh, Dominik A1 - Verdugo-Escamilla, E. T1 - A comprehensive methodology for monitoring evaporitic mineral precipitation and hydrochemical evolution of saline lakes: The case of Lake Magadi soda brine (East African Rift Valley, Kenya) JF - Crystal growth and design N2 - Lake Magadi, East African Rift Valley, is a hyperalkaline and saline soda lake highly enriched in Na+, K+, CO32–, Cl–, HCO3–, and SiO2 and depleted in Ca2+ and Mg2+, where thick evaporite deposits and siliceous sediments have been forming for 100 000 years. The hydrogeochemistry and the evaporite deposits of soda lakes are subjects of growing interest in paleoclimatology, astrobiology, and planetary sciences. In Lake Magadi, different hydrates of sodium carbonate/bicarbonate and other saline minerals precipitate. The precipitation sequence of these minerals is a key for understanding the hydrochemical evolution, the paleoenvironmental conditions of ancient evaporite deposits, and industrial crystallization. However, accurate determination of the precipitation sequence of these minerals was challenging due to the dependency of the different hydrates on temperature, water activity, pH and pCO2, which could induce phase transformation and secondary mineral precipitation during sample handling. Here, we report a comprehensive methodology applied for monitoring the evaporitic mineral precipitation and hydrochemical evolution of Lake Magadi. Evaporation and mineral precipitations were monitored by using in situ video microscopy and synchrotron X-ray diffraction of acoustically levitated droplets. The mineral patterns were characterized by ex situ Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. Experiments were coupled with thermodynamic models to understand the evaporation and precipitation-driven hydrochemical evolution of brines. Our results closely reproduced the mineral assemblages, patterns, and textural relations observed in the natural setting. Alkaline earth carbonates and fluorite were predicted to precipitate first followed by siliceous sediments. Among the salts, dendritic and acicular trona precipitate first via fractional crystallization─reminiscent of grasslike trona layers of Lake Magadi. Halite/villiaumite, thermonatrite, and sylvite precipitate sequentially after trona from residual brines depleted in HCO3–. The precipitation of these minerals between trona crystals resembles the precipitation process observed in the interstitial brines of the trona layers. Thermonatrite precipitation began after trona equilibrated with the residual brines due to the absence of excess CO2 input. We have shown that evaporation and mineral precipitation are the major drivers for the formation of hyperalkaline, saline, and SiO2-rich brines. The discrepancy between predicted and actual sulfate and phosphate ion concentrations implies the biological cycling of these ions. The combination of different in situ and ex situ methods and modeling is key to understanding the mineral phases, precipitation sequences, and textural relations of modern and ancient evaporite deposits. The synergy of these methods could be applicable in industrial crystallization and natural brines to reconstruct the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and extraterrestrial planets. KW - Crystallization KW - Precipitation KW - Crystals KW - Evaporation KW - Minerals PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546712 DO - https://doi.org/10.1021/acs.cgd.1c01391 SN - 1528-7483 VL - 22 IS - 4 SP - 2307 EP - 2317 PB - ACS Publications CY - Washington, DC AN - OPUS4-54671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Zorn, R. A1 - Böhning, Martin A1 - Wolff, M. A1 - Zamponi, M. A1 - Schönhals, Andreas T1 - Molecular mobility in high-performance polynorbornenes:A combined broadband dielectric, advanced calorimetry,and neutron scattering investigation JF - Polymer Engineering and Science N2 - The molecular dynamics of two addition type polynorbornenes, exo-PNBSiand PTCNSi1, bearing microporosity has been investigated by broadbanddielectric spectroscopy, fast scanning calorimetry, and neutron scattering. Bothpolymers have the same side groups but different backbones. Due to theirfavorable transport properties, these polymers have potential applications inseparation membranes for gases. It is established in literature that molecularfluctuations are important for the diffusion of small molecules through poly-mers. For exo-PNBSi, two dielectric processes are observed, which are assignedto Maxwell/Wagner/Sillars (MWS) process due to blocking of charge carriersat internal voids or pore walls. For PTCNSi1, one MWS-polarization process isfound. This points to a bimodal pore-size distribution for exo-PNBSi. A glasstransition for exo-PNBSi and for PTCNSi1 could be evidenced for the first timeusing fast scanning calorimetry. For Tgand the corresponding apparent activa-tion energy, higher values were found for PTCNSi1 compared to exo-PNBSi.For both polymers, the neutron scattering data reveal one relaxation process.This process is mainly assigned to methyl group rotation probably overlayedby carbon–carbon torsional fluctuations. KW - Advanced calorimetry KW - Dielectric spectroscopy KW - Neutron scattering KW - Polynorbornenes PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547086 DO - https://doi.org/10.1002/pen.25995 SN - 0032-3888 VL - 62 IS - 7 SP - 2143 EP - 2155 PB - Wiley AN - OPUS4-54708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - C. Pardo Pérez, L. A1 - Arndt, A. A1 - Stojkovikj, S. A1 - Y. Ahmet, I. A1 - T. Arens,, J. A1 - Dattila, F. A1 - Wendt, R. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Davies, V. A1 - Höflich, K. A1 - Köhnen, E. A1 - Tockhorn, P. A1 - Golnak, R. A1 - Xiao, J. A1 - Schuck, G. A1 - Wollgarten, M. A1 - López, N. A1 - T. Mayer, M. T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy JF - Advanced Energy Materials N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts. KW - Electrochemical CO2 conversion KW - Cu catalysts KW - X-ray absorption spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116 DO - https://doi.org/10.1002/aenm.202103328 SN - 1614-6832 VL - 12 IS - 5 SP - 2103328 PB - Wiley-VCH GmbH AN - OPUS4-54711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Almalla, A. A1 - Özcan Sandikcioglu, Özlem A1 - Witt, Julia T1 - In Situ Atomic Force Microscopy Analysis of the Corrosion Processes at the Buried Interface of an Epoxy-like Model Organic Film and AA2024-T3 Aluminum Alloy JF - Advanced Engineering Materials N2 - The application of characterization methods with high spatial resolution to the analysis of buried coating/metal interfaces requires the design and use of model systems. Herein, an epoxy-like thin film is used as a model coating resembling the epoxy-based coatings and adhesives widely used in technical applications. Spin coating is used for the deposition of a 30 nm-thin bilayer (BL) composed of poly-(ethylenimine) (PEI) and poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER). Fourier-transform infrared spectroscopy (FTIR) results confirm that the exposure of coated AA2024-T3 (AA) samples to the corrosive electrolyte solution does not cause the degradation of the polymer layer. In situ atomic force microscopy (AFM) studies are performed to monitor local corrosion processes at the buried interface of the epoxy-like film and the AA2024-T3 aluminum alloy surface in an aqueous electrolyte solution. Hydrogen evolution due to the reduction of water as the cathodic corrosion reaction leads to local blister formation. Based on the results of the complementary energy-dispersive X-ray spectroscopy (EDX) analysis performed at the same region of interest, most of the hydrogen evolved originates at the vicinity of Mg-containing intermetallic particles. KW - Scanning Kelvin probe force microscopy KW - Aluminum alloys KW - Buried interfaces KW - In situ atomic force microscopy KW - Local corrosion PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546932 DO - https://doi.org/10.1002/adem.202101342 SN - 1438-1656 SP - 1 EP - 9 PB - Wiley VHC-Verlag AN - OPUS4-54693 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sözen, H.I. A1 - Mendive-Tapia, E. A1 - Hickel, Tilmann A1 - Neugebauer, J. T1 - Ab initio investigations of point and complex defect structures in B2-FeAl JF - Physical review materials N2 - We study single-site and two-site defect structures in B2-type Fe-Al alloys by means of density functional theory supercell calculations. The defect formation energies are calculated as functions of the chemical potential, which are used to obtain the dependence of the defect concentrations on Al content at different temperatures. We also examine the converging behavior of the formation energies with respect to the supercell size to study the corresponding limit of dilute defects. The effect of magnetism is investigated by considering nonmagnetic, ferromagnetic, and paramagnetic states, calculations for the latter showing that the magnitude of the local magnetic moments strongly impacts the defect formation energies. The methodological studies are used to provide explanations for the wide spread of defect formation energies reported by experiments and other theoretical investigations. Based on these insights, the stability of the B2-FeAl structure as a function of Al concentration is obtained and discussed. KW - Atomistic models KW - Defects KW - Thermodynamics PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546956 DO - https://doi.org/10.1103/PhysRevMaterials.6.023603 SN - 2475-9953 VL - 6 IS - 2 SP - 1 EP - 11 PB - APS CY - College Park, MD AN - OPUS4-54695 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hieu, D.T. A1 - Kosslick, H. A1 - Riaz, M. A1 - Schulz, A. A1 - Springer, A. A1 - Frank, M. A1 - Jäger, Christian A1 - Minh Thu, N.T. A1 - Son, L.T. T1 - Acidity and Stability of Bronsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol JF - Catalysts N2 - Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 ◦C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 ◦C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 ◦C. Although a part of the clinoptilolite framework is maintained up to 600 ◦C, a loss of crystallinity is already observed starting from 450 ◦C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 ◦C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 ◦C. A part of the Brønsted sites is lost after calcination specifically at 500 ◦C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1 -C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 ◦C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 ◦C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused. KW - Etherification KW - Glycerol KW - Zeolite KW - Clinoptilolite KW - Bronsted acidity KW - Dehydroxylation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546982 DO - https://doi.org/10.3390/catal12030253 VL - 12 IS - 3 SP - 1 EP - 24 PB - MDPI AN - OPUS4-54698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stawski, Tomasz A1 - Van Driessche, A. E. S. T1 - Editorial for special issue "Formation of sulfate minerals in natural and industrial environments" JF - Minerals N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods. KW - Calcium sulfate KW - Sulfates PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546794 DO - https://doi.org/10.3390/min12030299 SN - 2075-163X VL - 12(3) IS - Special issue "Formation of sulfate minerals in natural and industrial environments" SP - 1 EP - 3 PB - MDPI CY - Basel AN - OPUS4-54679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Ines A1 - Al-Sabbagh, Dominik A1 - Bentrup, U. A1 - Marquardt, Julien A1 - Schmid, Thomas A1 - Scoppola, E. A1 - Kraus, Werner A1 - Stawski, Tomasz A1 - de Oliveira Guilherme Buzanich, Ana A1 - Yusenko, Kirill A1 - Weidner, Steffen A1 - Emmerling, Franziska T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate JF - Chemistry - A European Journal N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure. KW - Bismuth KW - In situ EXAFS KW - In situ SAXS/WAXS KW - Lacunary Keggin ion KW - Polyoxometalates KW - Self-assembly PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823 DO - https://doi.org/10.1002/chem.202200079 SN - 0947-6539 VL - 28 IS - 27 SP - 1 EP - 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Feldmann, Ines A1 - Emmerling, Franziska T1 - Mix and wait – a relaxed way for synthesizing ZIF-8 JF - RSC Advances N2 - Herein we report the synthesis of a zeolitic imidazolate framework (ZIF-8) by an easy “mix and wait” procedure. In a closed vial, without any interference, the mixture of 2-methylimidazole and basic zinc carbonate assembles into the crystalline product with approx. 90% conversion after 70 h. The reaction exhibits sigmoidal kinetics due to the self-generated water which accelerates the reaction. KW - In-situ analysis KW - Mechanochemistry KW - MOF KW - Synthesis KW - ZIF-8 PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546841 DO - https://doi.org/10.1039/D2RA00740A VL - 12 SP - 8940 EP - 8944 PB - Royal Society of Chemistry AN - OPUS4-54684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Crouzier, L. A1 - Feltin, N. A1 - Delvallée, A. A1 - Pellegrino, Francesco A1 - Maurino, V. A1 - Cios, Grzegorz A1 - Tokarski, T. A1 - Salzmann, Christoph A1 - Deumer, J. A1 - Gollwitzer, C. A1 - Hodoroaba, Vasile-Dan T1 - Correlative analysis of the dimensional properties of bipyramidal titania nanoparticles by complementing electron microscopy with other methods JF - Nanomaterials N2 - In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano‐bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron‐transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM‐in‐SEM (or T‐SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X‐ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab‐initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration. KW - Nanoparticles KW - Complex-shape KW - Bipyramid KW - Electron microscopy KW - AFM KW - Size measurements KW - TKD KW - STEM-in-SEM KW - SAXS KW - Nanoparticle concentration KW - Correlative analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539888 DO - https://doi.org/10.3390/nano11123359 SN - 2079-4991 VL - 11 IS - 12 SP - 1 EP - 19 PB - MDPI CY - Basel AN - OPUS4-53988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Gräf, S. T1 - Ten Open Questions about Laser-Induced Periodic Surface Structures JF - Nanomaterials N2 - Laser-induced periodic surface structures (LIPSS) are a simple and robust route for the nanostructuring of solids that can create various surface functionalities featuring applications in optics, medicine, tribology, energy technologies, etc. While the current laser technologies already allow surface processing rates at the level of m2/min, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry, as well as by limitations in controlling the processing of LIPSS and in the long-term stability of the created surface functions. This Perspective article aims to identify some open questions about LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, we intend to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry. KW - Laser-induced periodic surface structures (LIPSS) KW - Industrial application KW - Functional properties KW - Surface functionalization KW - Modelling PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539503 DO - https://doi.org/10.3390/nano11123326 SN - 2079-4991 VL - 11 IS - 12 SP - 1 EP - 21 PB - MDPI CY - Basel, Switzerland AN - OPUS4-53950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Climent Terol, Estela A1 - Gojani, Ardian A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles JF - Advanced Engineering Materials N2 - The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self-written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field-of-view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer-sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained. KW - Core–shell particles KW - Image analysis KW - Nanoparticles KW - Roughness KW - SEM KW - transmission mode PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542576 DO - https://doi.org/10.1002/adem.202101344 SP - 1 EP - 9 PB - Wiley-VCH AN - OPUS4-54257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yusenko, Kirill A1 - Kabelitz, Anke A1 - Schokel, Alexander A1 - Wagner, Ralf A1 - Prinz, Carsten A1 - Kemnitz, E A1 - Emmerling, Franziska A1 - Krahl, Thoralf A1 - de Oliveira Guilherme Buzanich, Ana T1 - Local Structure of Europium-Doped Luminescent Strontium Fluoride Nanoparticles: Comparative X-ray Absorption Spectroscopy and Diffraction Study JF - ChemNanoMat N2 - Rare-earth based luminescent materials are key functional components for the rational design of light-conversion smart devices. Stable Eu3+-doped strontium fluoride (SrF2) nanoparticles were prepared at room temperature in ethylene glycol. Their luminescence depends on the Eu content and changes after heat treatment. The crystallinity of heat-treated material increases in comparison with as-synthesized samples. Particles were investigated in solution using X-ray diffraction, small-angle X-ray scattering, and X-ray spectroscopy. After heat treatment, the size of the disordered nanoparticles increases together with a change of their local structure. Interstitial fluoride ions can be localized near Eu3+ ions. Therefore, non-radiative relaxation from other mechanisms is decreased. Knowledge about the cation distribution is key information for understanding the luminescence properties of any material. KW - SrF2 KW - EXAFS KW - Eu PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540094 DO - https://doi.org/10.1002/cnma.202100281 VL - 7 IS - 11 SP - 1221 EP - 1229 PB - Wiley Online Library AN - OPUS4-54009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Serebrennikova, P. A1 - Komarov, V. A1 - Sukhikh, A. A1 - Khranenko, S. A1 - Zadesenetz, A. A1 - Gromilov, S A1 - Yusenko, Kirill T1 - [NiEn3](MoO4)0.5(WO4)0.5 co-crystals as single-source precursors for ternary refractory Ni-Mo-W alloys JF - Nanomaterials N2 - The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown. KW - Single source precursors KW - Phase diagrams PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540123 DO - https://doi.org/10.3390/nano11123272 VL - 11 IS - 12 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-54012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Scheliga, F. T1 - Ring-Expansion Polymerization of 𝝐-Caprolactone, Glycolide, and l-lactide with a Spirocyclic Tin(IV) Catalyst Derived from or 2,2′-Dihydroxy-1,1′-Binaphthyl – New Results and a Revision JF - Macromolecular Chemistry and Physics N2 - In contrast to other cyclic tin bisphenoxides, polymerizations of glycolide and l-lactide with the spirocyclic tin(IV) bis-1,1′-bisnapthoxide yield linear chains having a 1,1′-bisnapthol end group and no cycles. In the case of l-lactide, LA/Cat ratio and temperature are varied and at 160 °C or below, all polylactides mainly consist of even-numbered chains. A total predominance of even-numbered chains is also found for homopolymerization of glycolide, or the copolymerization of glycolide and l-lactide, when conducted <120 °C. Linear chains having a bisnaphthol end group are again the main reaction products of ring-expansion polymerizations (REP) of 𝝐-caprolactone, but above 150 °C cycles are also formed. KW - Polylactide KW - MALDI-TOF MS KW - Polymerization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541931 DO - https://doi.org/10.1002/macp.202100308 VL - 222 IS - 24 SP - 1 EP - 10 PB - Wiley VCH GmbH AN - OPUS4-54193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sreekala, L. A1 - Dey, P. A1 - Hickel, Tilmann A1 - Neugebauer, J. T1 - Unveiling nonmonotonic chemical trends in the solubility of H in complex Fe-Cr-Mn carbides by means of ab initio based approaches JF - Physical review materials N2 - The microstructure of advanced high-strength steels often shows a sensitive dependence on alloying. For example, adding Cr to improve the corrosion resistance of medium-Mn steels also enhances the precipitation of carbides. The current study focuses on the behavior of H in such complex multicomponent carbides by employing different methodological strategies. We systematically analyze the impact of Cr, Mn, and Fe using density functional theory (DFT) for two prototype precipitate phases, M3C and M23C6, where M represents the metal sublattice. Our results show that the addition of these alloying elements yields strong nonmonotonic chemical trends for the H solubility. We identify magnetovolume effects as the origin for this behavior, which depend on the considered system, the sites occupied by H, and short- vs long-range interactions between H and the alloying elements. We further show that the H solubility is directly correlated with the occupation of its nearest-neighbor shells by Cr and Mn. Based on these insights, DFT data from H containing binary-metal carbides are used to design a ridge regression based model that predicts the solubility of H in the ternary-metal carbides (Fe-Cr-Mn-C). KW - Hydrogen KW - High-strength steel KW - Carbide KW - Ab initio KW - Complexity PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542271 DO - https://doi.org/10.1103/PhysRevMaterials.6.014403 SN - 2475-9953 VL - 6 IS - 1 SP - 1 EP - 14 PB - American Physical Society (APS) CY - College Park, MD AN - OPUS4-54227 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - MacLean, J. A1 - Mayanna, S. A1 - Benning, L. G. A1 - Horn, F. A1 - Bartholomäus, A. A1 - Wiesner, Yosri A1 - Wagner, D. A1 - Liebner, S. T1 - The terrestrial plastisphere: Diversity and polymer-colonizing potential of plastic-associated microbial communities in soil JF - Microorganisms N2 - The concept of a ‘plastisphere microbial community’ arose from research on aquatic plastic debris, while the effect of plastics on microbial communities in soils remains poorly understood. Therefore, we examined the inhabiting microbial communities of two plastic debris ecosystems with regard to their diversity and composition relative to plastic-free soils from the same area using 16S rRNA amplicon sequencing. Furthermore, we studied the plastic-colonizing potential of bacteria originating from both study sites as a measure of surface adhesion to UV-weathered polyethylene (PE) using high-magnification field emission scanning electron microscopy (FESEM). The high plastic content of the soils was associated with a reduced alpha diversity and a significantly different structure of the microbial communities. The presence of plastic debris in soils did not specifically enrich bacteria known to degrade plastic, as suggested by earlier studies, but rather shifted the microbial community towards highly abundant autotrophic bacteria potentially tolerant to hydrophobic environments and known to be important for biocrust formation. The bacterial inoculates from both sites formed dense biofilms on the surface and in micrometer-scale surface cracks of the UV-weathered PE chips after 100 days of in vitro incubation with visible threadlike EPS structures and cross-connections enabling surface adhesion. High-resolution FESEM imaging further indicates that the microbial colonization catalyzed some of the surface degradation of PE. In essence, this study suggests the concept of a ‘terrestrial plastisphere’ as a diverse consortium of microorganisms including autotrophs and other pioneering species paving the way for those members of the consortium that may eventually break down the plastic compounds. KW - Soil microbial community KW - Polyethylene colonization KW - Plastic pollution PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542790 DO - https://doi.org/10.3390/microorganisms9091876 VL - 9 IS - 9 SP - 1 EP - 19 PB - MDPI CY - Basel AN - OPUS4-54279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reed, B.P. A1 - Radnik, Jörg A1 - Shard, A.G. T1 - Ionic liquid [PMIM]+[NTf2]− (Solarpur®) characterized by XPS JF - Surface Science Spectra N2 - X-ray photoelectron spectroscopy (XPS) was performed on the meniscus of a droplet of ionic liquid 1-propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl) imide [PMIM]+[NTf2]− (Solarpur®) in ultrahigh vacuum. High-resolution spectra of F 1s, O 1s, N 1s, C 1s, and S 2p are presented along with a survey spectrum and the valence band structure. The spectra presented here were generated using monochromatic Al Kα radiation (1486.6 eV). KW - Ionic liquid KW - 1-propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide KW - X-ray Photoelectron Spectroscopy PY - 2022 DO - https://doi.org/10.1116/6.0001518 VL - 29 IS - 1 SP - 014001-1 PB - AVS AN - OPUS4-54335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -