TY - JOUR A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Lippitz, Andreas A1 - Hodoroaba, Vasile-Dan A1 - Schmid, Thomas A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Zirconium permanent modifiers for graphite furnaces used in absorption spectrometry: understanding their structure and mechanism of action JF - Journal of Analytical Atomic Spectrometry N2 - The mechanism of action of zirconium permanent modifiers on graphite surfaces was investigated in order to understand its influence on the analytical signal in atomic and molecular absorption spectrometry (AAS/MAS). For this, the molecule formation of CaF was studied, which is used for the indirect analytical determination of fluorine in high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). The kinetics of this reaction was established by monitoring its molecular spectrum at different atomisation temperatures. An Arrhenius plot showed a pseudo-first order reaction with respect to fluorine (n = 1). An intermediate state was isolated, and its structure was elucidated by spectroscopic methods: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEMEDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES and EXAFS), and Raman microspectroscopy. We propose here a mechanism, where ZrO2 acts as a heterogeneous catalyst: after a pyrolytic step, an intermediate state of ZrO(OCaF) is activated, and at higher temperatures, CaF(g) is released from the zirconium-coated graphite surface. No evidence of the formation of zirconium carbide was found. Consequently, as the CaF formation is catalysed by a heterogeneous catalyst, surface modifications with ZrO2 nanoparticles and ZrO xerogels were investigated in order to increase the surface area. Their influence was evaluated in the molecule formation of CaF, CaCl, CaBr, and CaI. Graphite furnace modification with zirconium oxide nanoparticles proves to be the best choice for fluorine analysis with a signal enhancement of more than eleven times with respect a non-coated graphite furnace. However, the influence of zirconium modifications in the analytical signals of Cl, and I is lower than the F signals or even negative in case of the Br. Understanding zirconium modifiers as heterogeneous catalysts offers a new perspective to AAS and MAS, and reveals the potential of surface analytical methods for development of improved permanent modifiers and graphite furnace coatings. KW - Zirconium KW - HR-CS-MAS KW - Graphite furnace KW - Nanoparticles KW - Xerogel KW - Calcium monofluoride KW - Absorption spectrometry PY - 2018 UR - https://pubs.rsc.org/en/content/articlelanding/2018/ja/c8ja00190a DO - https://doi.org/10.1039/C8JA00190A SN - 0267-9477 VL - 33 IS - 12 SP - 2034 EP - 2042 PB - Royal Society of Chemistry AN - OPUS4-46775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdel-Wakil, W. A1 - Fahmy, Alaa A1 - Kamoun, E. A1 - Hassan, W. A1 - Abdelhai, Q. A1 - Salama, T. T1 - A New Route for Synthesis of Polyurethanevinyl Acetate Acrylate Emulsions as Binders for Pigment Printing of Cotton Fabrics JF - Egyptian Journal of Chemistry N2 - Herein, two polyurethane oligomers were successfully synthesized using a prepolymer mixing process. The prepolymers were synthesized based on the step-growth addition polymerization of polypropylene glycol, Methylene diphenyl diisocyanate and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was functioned as the isocyanate blocking agent. Thereafter, different terpolymer emulsions were prepared by the emulsion graft copolymerization with the vinyl acetate monomer in presence of 2-ethylhexyl acrylate as a vinyl monomer. The chemical structures of the synthesized oligomeric monomers were probed by FTIR spectroscopy and found to vary with the content of acrylic monomer used in the oligomer synthesis phase (i.e.hydroxyethyl acrylate or hydroxyethyl methacrylate). The topography, thermal stability, and particle size of terpolymers were investigated by SEM, TGA, and zeta potential, respectively. The TGA results demonstrated marked enhancement in thermal stability of the synthesized terpolymers up to ca. 600°C, which was concurrent with enhanced surface homogeneity and film properties as evidenced by the SEM images. These terpolymers showed also property enhancement as binders for textile pigment printing in terms of rubbing resistance, color strength and fastness to washing when compared to the commercial binders. These judgments would provide a new competent synthesis route by introducing polyurethane acetate vinyl acrylate as the binder for use in pigment printing of cotton fabrics. KW - Vinyl monomer KW - Polyurethane acetate vinyl acrylate KW - Surface coating KW - Terpolymer KW - Textile binder PY - 2020 DO - https://doi.org/10.21608/ejchem.2020.21712.2292 VL - 63 IS - 3 SP - 1063 EP - 1073 AN - OPUS4-52300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abusafia, A. A1 - Scheid, C. A1 - Meurer, Maren A1 - Altmann, Korinna A1 - Dittmer, U. A1 - Steinmetz, H. T1 - Microplastic sampling strategies in urban drainage systems for quantification of urban emissions based on transport pathways JF - Applied Research N2 - Tracking waterborne microplastic (MP) in urban areas is a challenging task because of the various sources and transport pathways involved. Since MP occurs in low concentrations in most wastewater and stormwater streams, large sample volumes need to be captured, prepared, and carefully analyzed. The recent research in urban areas focused mainly on MP emissions at wastewater treatment plants (WWTPs), as obvious entry points into receiving waters. However, important transport pathways under wet-weather conditions are yet not been investigated thoroughly. In addition, the lack of comprehensive and comparable sampling strategies complicated the attempts for a deeper understanding of occurrence and sources. The goal of this paper is to (i) introduce and describe sampling strategies for MP at different locations in a municipal catchment area under dry and wet-weather conditions, (ii) quantify MP emissions from the entire catchment and two other smaller ones within the bigger catchment, and (iii) compare the emissions under dry and wet-weather conditions. WWTP has a high removal rate of MP (>96%), with an estimated emission rate of 189 kg/a or 0.94 g/[population equivalents (PEQ · a)], and polyethylene (PE) as the most abundant MP. The specific dry-weather emissions at a subcatchment were ≈30 g/(PEQ · a) higher than in the influent of WWTP with 23 g/(PEQ · a). Specific wet-weather emissions from large sub-catchment with higher traffic and population densities were 1952 g/(ha · a) higher than the emissions from smaller catchment (796 g/[ha · a]) with less population and traffic. The results suggest that wet-weather transport pathways are likely responsible for 2–4 times more MP emissions into receiving waters compared to dry-weather ones due to tire abrasion entered from streets through gullies. However, more investigations of wet-weather MP need to be carried out considering additional catchment attributes and storm event characteristics. KW - Combined sewer system KW - Large volume samplers KW - Microplastic pollution KW - Separate sewer system KW - Stormwater retention tank PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568271 DO - https://doi.org/10.1002/appl.202200056 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-56827 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 - Acosta-Zepeda, C. A1 - Saavedra, P. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Modeling of silicon surface topographies induced by single nanosecond laser pulse induced melt-flows JF - Journal of Applied Physics N2 - Irradiation with a single nanosecond laser pulse in the melting regime can result in a characteristic change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In this work, the dimple height, depth, and width are modeled following and extending in a more rigorous manner the approach of Wood and Giles [Phys. Rev. B 23, 2923–2942 (1981)] and that of Schwarz-Selinger and coworkers [Phys. Rev. B 64, 155323 (2001)], upon varying the laser irradiation parameters such as peak energy density, pulse duration, and wavelength. This is achieved with numerical simulations of one-dimensional heat flow as input to the analytical fluid-flow equations. KW - Nanosecond laser KW - Melting KW - Silicon KW - Fluid-flow PY - 2019 DO - https://doi.org/10.1063/1.5053918 SN - 0021-8979 SN - 1089-7550 VL - 125 IS - 17 SP - 175101-1 EP - 175101-9 PB - AIP Publishing CY - Melville, USA AN - OPUS4-47927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Acosta-Zepeda, C. A1 - Saavedra, S. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Modelling of single UV nanosecond pulsed laser surface modifications of silicon JF - Laser Physics N2 - Irradiation with a single spatially Gaussian-shaped nanosecond laser pulse in the melting regime can result in a characteristic annular change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In a recent work we have investigated the induced changes in the surface topography upon exposure to wavelengths in the visible and near infrared spectral region. Irradiation in the UV requires a more detailed analysis due to the enhanced absorption of the material. In the present analysis, we determine under which conditions our previous model can be used and the corresponding results are presented. KW - Laser KW - Silicon KW - Surface modification PY - 2020 DO - https://doi.org/10.1088/1555-6611/ab9b2c SN - 1555-6611 SN - 1054-660X VL - 30 IS - 8 SP - 086003-1 EP - 086003-4 PB - IOP Publishing / Astro Ltd CY - Bristol, United Kingdom AN - OPUS4-51022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Afantitis, A. A1 - Melagraki, G. A1 - Isigonis, P. A1 - Tsoumanis, A. A1 - Varsou, D. D. A1 - Valsami-Jones, E. A1 - Papadiamantis, A. A1 - Ellis, L.-J. A. A1 - Sarimveis, H. A1 - Doganis, P. A1 - Karatzas, P. A1 - Tsiros, P. A1 - Liampa, I. A1 - Lobaskin, V. A1 - Greco, D. A1 - Serra, A. A1 - Kinaret, P. A. S. A1 - Saarimäki, L. A. A1 - Grafström, R. A1 - Kohonen, P. A1 - Nymark, P. A1 - Willighagen, E. A1 - Puzyn, T. A1 - Rybinska-Fryca, A. A1 - Lyubartsev, A. A1 - Jensen, K. A. A1 - Brandenburg, J. G. A1 - Lofts, S. A1 - Svendsen, C. A1 - Harrison, S. A1 - Maier, D. A1 - Tamm, K. A1 - Jänes, J. A1 - Sikk, L. A1 - Dusinska, M. A1 - Longhin, E. A1 - Rundén-Pran, E. A1 - Mariussen, E. A1 - El Yamani, N. A1 - Unger, Wolfgang A1 - Radnik, Jörg A1 - Tropsha, A. A1 - Cohen, Y. A1 - Lesczynski, J. A1 - Hendren, C. O. A1 - Wiesner, M. A1 - Winkler, D. A1 - Suzuki, N. A1 - Yoon, T. H. A1 - Choi, J.-S. A1 - Sanabria, N. A1 - Gulumian, M. A1 - Lynch, I. T1 - NanoSolveIT Project: Driving nanoinformatics research to develop innovative and integrated tools for in silico nanosafety assessment JF - Computational and Structural Biotechnology Journal N2 - Nanotechnology has enabled the discovery of a multitude of novel materials exhibiting unique physicochemical (PChem) properties compared to their bulk analogues. These properties have led to a rapidly increasing range of commercial applications; this, however, may come at a cost, if an association to long-term health and environmental risks is discovered or even just perceived. Many nanomaterials (NMs) have not yet had their potential adverse biological effects fully assessed, due to costs and time constraints associated with the experimental assessment, frequently involving animals. Here, the available NM libraries are analyzed for their suitability for integration with novel nanoinformatics approaches and for the development of NM specific Integrated Approaches to Testing and Assessment (IATA) for human and environmental risk assessment, all within the NanoSolveIT cloud-platform. These established and well-characterized NM libraries (e.g. NanoMILE, NanoSolutions, NANoREG, NanoFASE, caLIBRAte, NanoTEST and the Nanomaterial Registry (>2000 NMs)) contain physicochemical characterization data as well as data for several relevant biological endpoints, assessed in part using harmonized Organisation for Economic Co-operation and Development (OECD) methods and test guidelines. Integration of such extensive NM information sources with the latest nanoinformatics methods will allow NanoSolveIT to model the relationships between NM structure (morphology), properties and their adverse effects and to predict the effects of other NMs for which less data is available. The project specifically addresses the needs of regulatory agencies and industry to effectively and rapidly evaluate the exposure, NM hazard and risk from nanomaterials and nano-enabled products, enabling implementation of computational ‘safe-by-design’ approaches to facilitate NM commercialization. KW - Nanoinformatics KW - Hazard assessment KW - (Quantitative) Structure-Active Relationships KW - Safe-by-design KW - Predictive modelling PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505952 DO - https://doi.org/10.1016/j.csbj.2020.02.023 VL - 18 SP - 583 EP - 602 PB - Elsevier B.V. AN - OPUS4-50595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agostini, G. A1 - Radnik, Jörg T1 - Spectroscopy in Catalysis JF - Catalysts N2 - Knowledge-based catalyst development is always an interaction between preparation, analysis and catalytic testing. Only if these three factors fit together can success be expected. For the analytic side of this triangle, spectroscopic methods play a crucial role. Whereas with diffraction, scattering and microscopy, decisive insights into the structure and morphology of the catalysts can be obtained, spectroscopy produces new knowledge about the chemical nature of the catalyst, e.g., its bonding and valence states. KW - Spectroscopy KW - Catalysis KW - Operando KW - In situ PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506507 DO - https://doi.org/10.3390/catal10040408 VL - 10 IS - 4 SP - 408 PB - MDPI CY - Basel AN - OPUS4-50650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, R. A1 - Vaishampayan, A. A1 - Cuellar-Camacho, J. L. A1 - Wight, D. J. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang A1 - Grohmann, E. A1 - Haag, R. A1 - Wagner, O. T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density JF - Advance Material Interfaces N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies. KW - Surface charge KW - Bacteria KW - Graphene oxide KW - Escherichia coli KW - XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651 DO - https://doi.org/10.1002/admi.201902066 VL - 7 IS - 15 SP - 1902066 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Akbar, S. A1 - Hasanain, S.K. A1 - Ivashenko, O. A1 - Dutka, M.V. A1 - Akhtar, N. A1 - De Hosson, J.Th.M. A1 - Ali, Naveed A1 - Rudolf, P. T1 - Defect ferromagnetism in SnO2:Zn2+ hierarchical nanostructures: correlation between structural, electronic and magnetic properties JF - RSC Advances N2 - We report on the ferromagnetism of Sn1-xZnxO2 (x < 0.1) hierarchical nanostructures with various morphologies synthesized by a solvothermal route. A room temperature ferromagnetic and paramagnetic response was observed for all compositions, with a maximum in ferromagnetism for x = 0.04. The ferromagnetic behaviour was found to correlate with the presence of zinc on substitutional Sn sites and with a low oxygen vacancy concentration in the samples. The morphology of the nanostructures varied with zinc concentration. The strongest ferromagnetic response was observed in nanostructures with well-formed shapes, having nanoneedles on their surfaces. These nanoneedles consist of (110) and (101) planes, which are understood to be important in stabilizing the ferromagnetic defects. At higher zinc concentration the nanostructures become eroded and agglomerated, a phenomenon accompanied with a strong decrease in their ferromagnetic response. The observed trends are explained in the light of recent computational studies that discuss the relative stability of ferromagnetic defects on various surfaces and the role of oxygen vacancies in degrading ferromagnetism via an increase in free electron concentration. KW - Ferromagnetism KW - Nanostructures KW - Magnetic properties PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473014 DO - https://doi.org/10.1039/c9ra00455f SN - 2046-2069 VL - 9 IS - 7 SP - 4082 EP - 4091 PB - Royal Society of Chemistry AN - OPUS4-47301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Akhmetova, Irina A1 - Beyer, Sebastian A1 - Schutjajew, K. A1 - Tichter, T. A1 - Wilke, Manuel A1 - Prinz, Carsten A1 - B. Martins, Inês C. A1 - Al-Sabbagh, Dominik A1 - Roth, C. A1 - Emmerling, Franziska T1 - Cadmium benzylphosphonates - the close relationship between structure and properties JF - CrystEngComm N2 - Cadmium benzylphosphonate Cd(O3PBn)·H2O and its fluorinated derivates Cd(O3PBn-3F)·H2O, Cd(O3PBn-4F)·H2O, and Cd(O3PBn-F5)·H2O were synthesized mechanochemically. The Crystal structures of the compounds were determined based on powder X-ray diffraction (PXRD) data. The influence of the ligand substitution on the crystal structure of the metal phosphonate was determined. The hydrophobicity as a function of degree of fluorination was investigated using dynamic vapor sorption. KW - Mechanochemistry KW - Metal phosphonates KW - PXRD KW - DVS PY - 2019 DO - https://doi.org/10.1039/c9ce00776h VL - 21 SP - 5958 EP - 5964 PB - RSC Royal Society of Chemistry AN - OPUS4-49930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Akhmetova, Irina A1 - Schuzjajew, K. A1 - Wilke, M. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Rademann, K. A1 - Roth, C. A1 - Emmerling, Franziska T1 - Synthesis, characterization and in situ monitoring of the mechanochemical reaction process of two manganese(II)-phosphonates with N-containing ligands JF - Journal of Materials Science N2 - Two divalent manganese aminophosphonates, manganese mono (nitrilotrimethylphosphonate) (MnNP3) and manganese bis N-(carboxymethyl)iminodi(methylphosphonate)) (Mn(NP2AH)2), have been prepared by mechanochemical synthesis and characterized by powder X-ray diffraction (PXRD). The structure of the novel compound Mn(NP2AH)2 was determined from PXRD data. MnNP3 as well as Mn(NP2AH)2 exhibits a chain-like structure. In both cases, the manganese atom is coordinated by six oxygen atoms in a distorted octahedron. The local coordination around Mn was further characterized by extended X-ray absorption fine structure. The synthesis process was followed in situ by synchrotron X-ray diffraction revealing a three-step reaction mechanism. The asprepared manganese(II) phosphonates were calcined on air. All samples were successfully tested for their suitability as catalyst material in the oxygen evolution reaction. KW - Mechanochemistry KW - In situ KW - XRD PY - 2018 DO - https://doi.org/10.1007/s10853-018-2608-6 SN - 0022-2461 SN - 1573-4803 VL - 53 IS - 19 SP - 13390 EP - 13399 PB - Springer Science + Business Media B.V. AN - OPUS4-45673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Prinz, Carsten A1 - Scholz, Gudrun A1 - Kemnitz, Erhard A1 - Emmerling, Franziska T1 - Ca-, Sr-, and Ba-Coordination polymers based on anthranilic acid via mechanochemistry JF - Daltron Transaction N2 - Ca-, Sr-, and Ba-Based coordination polymers (CPs) were prepared mechanochemically by milling metal-hydroxide samples with anthranilic acid (oABAH). {[Ca(oABA)2(H2O)3]}n consists of one-dimensional polymeric chains that are further connected by a hydrogen-bonding network. {[Sr(oABA)2(H2O)2]·H2O}n is a one-dimensional CP in which water molecules bridge Sr2+ ions and increase the dimensionality by building an extended network. {[Ba(oABA)2(H2O)]}n crystallizes as a two-dimensional CP comprising one bridging water molecule. The cation radii influence the inorganic connectivity and dimensionality of the resulting crystal structures. The crystal structures were refined from powder X-ray diffraction data using the Rietveld method. The local coordination environments were studied via extended X-ray absorption fine structure (EXAFS) measurements. The compounds were further characterized using comprehensive analytical methods such as elemental analysis, thermal analysis, MAS NMR, imaging, and dynamic vapor sorption (DVS) measurements. Compounds 1, 2, and 3 exhibit small surface areas which decrease further after thermal annealing experiments. All compounds exhibit a phase transformation upon heating, which is only reversible in 3. KW - Mechanochemistry KW - XRD PY - 2019 DO - https://doi.org/10.1039/c9dt00991d SN - 1477-9226 SN - 1477-9234 VL - 48 IS - 19 SP - 6513 EP - 6521 PB - Royal Society of Chemistry AN - OPUS4-48014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Scholz, G. A1 - Prinz, Carsten A1 - Zimathies, Annett A1 - Emmerling, Franziska A1 - Kemnitz, E. T1 - Hydrated and dehydrated Ca-coordination polymers based on benzene-dicarboxylates: mechanochemical synthesis, structure refinement, and spectroscopic characterization JF - CrystEngComm N2 - A series of Ca-based coordination polymers were prepared mechanochemically by milling Ca(OH)2 with phthalic acid (H2oBDC), isophthalic acid (H2mBDC), and terephthalic acid (H2pBDC). The hydrated compounds [Ca(oBDC)(H2O)], [Ca(mBDC)(H2O)3.4], and [Ca(pBDC)(H2O)3] were prepared for the first time via mechanochemical routes. The refined structures were validated by extended X-ray absorption data. The new dehydrated compound [Ca(oBDC)] (1-H2O), obtained after the thermal post-treatment of 1 in a reversible phase transition process, was determined ab initio based on the powder X-ray diffraction (PXRD) data. The materials were thoroughly characterized using elemental analysis, thermal analysis, and spectroscopic methods: magic-angle spinning NMR and attenuated total reflection-infrared spectroscopy. The specific surface areas and sorption properties of the hydrated and dehydrated samples were determined using the isotherms of gas sorption and dynamic vapor sorption measurements. KW - Mechanochemistry KW - XRD PY - 2018 UR - http://pubs.rsc.org/en/content/articlehtml/2017/ce/c7ce01906h DO - https://doi.org/10.1039/C7CE01906H VL - 20 SP - 946 EP - 961 PB - Royal Society of Chemistry AN - OPUS4-44440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Scholz, Gudrun A1 - Emmerling, Franziska A1 - Kemnitz, Erhard T1 - Ca-Tetrafluorophthalate and Sr-isophthalate: mechanochemical synthesis and characterization in comparison with other Ca-and Sr-coordination polymers JF - Dalton Transactions N2 - New Ca- and Sr-based coordination polymers (CPs) were mechanochemically synthesized by milling metal hydroxide samples (M = Ca, Sr) with tetrafluorophthalic acid (H2oBDC-F4) and isophthalic acid (H2mBDC). [Ca(oBDC-F4)(H2O)2] (1) exhibits a small surface area which is slightly increased after removing the crystal water. On the other hand, the hydrated sample of the nonfluorinated [Sr(mBDC)(H2O)3.4] (2) reveals a small BET surface area which remains unchanged even after the release of crystal water via thermal treatment. The new compounds 1 and 2 are similar to their Sr- and Ca-analogs, respectively. These findings are confirmed by thermal analysis, MAS NMR, and ATR-IR measurements, in addition to the Le Bail refinements for the measured powder X-ray data of 1 and 2. Ca- and Sr-CPs based on perfluorinated dicarboxylic systems and their nonfluorinated analogs diverse in structural and chemical properties depending on the geometries of the organic linkers and the presence of fluorine atoms. The fluorinations of organic ligands lead to the formation of fluorinated CPs with higher dimensionalities compared to their nonfluorinated counterparts. Conversely, the thermal stabilities of the latter are higher than those of the fluorinated CPs. KW - Mechanochemistry PY - 2018 DO - https://doi.org/10.1039/c8dt00695d SN - 1477-9226 SN - 1477-9234 VL - 47 IS - 16 SP - 5743 EP - 5754 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-44696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Scholz, Gudrun A1 - Emmerling, Franziska A1 - Kemnitz, Erhard T1 - Barium coordination polymers based on fluorinated and fluorine-free benzene-dicarboxylates: Mechanochemical synthesis and spectroscopic characterization JF - Solid state sciences N2 - A series of new Ba-based coordination polymers (CPs) were mechanochemically synthesized by milling Ba-hydroxide samples with perfluorinated and fluorine-free benzene-dicarboxylic acids, including tetrafluoroisophthalic acid (H2mBDC-F4), tetrafluorophthalic acid (H2oBDC-F4), isophthalic acid (H2mBDC) and phthalic acid (H2oBDC). The new fluorinated CPs: [Ba(mBDC-F4)$0.5H2O] (1) and [Ba(oBDC-F4)·1.5H2O] (2) are compared to their nonfluorinated counterparts: [Ba(mBDC)·2.5H2O] (3), and [Ba(oBDC)·1H2O] (4). These materials are thoroughly characterized using powder X-ray diffraction. The products obtained by milling are all hydrated but vary in their water contents. Compositions and local structures are investigated by elemental analysis, thermal analysis, MAS NMR and attenuated total reflectioninfrared spectroscopy. These materials exhibit high thermal stabilities but small surface areas that remain unchanged even after thermal treatments. KW - Mechanochemical synthesis KW - Barium KW - Fluorine KW - Coordination polymers KW - PXRD KW - MAS NMR spectroscopy PY - 2018 UR - https://www.sciencedirect.com/science/article/pii/S1293255817310798 DO - https://doi.org/10.1016/j.solidstatesciences.2018.03.013 SN - 1293-2558 SN - 1873-3085 VL - 79 SP - 99 EP - 108 PB - Elsevier AN - OPUS4-44880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ali, Naveed A1 - Komal, N. A1 - Malik, Z. A1 - Chaudhary, A.J. T1 - Synthesis, characterization and properties of hierarchically assembled antimony oxyhalides nanonetworks JF - Materials research express N2 - The novel synthesis route has been developed for hierarchically structured; nanorods and nanosheets of Sb4O5Cl2 from a single precursor, with dimension range between 57–90 nm. X-ray powder diffraction analysis confirmed the monoclinic crystal symmetry in P21/c(14)with structure type Sb4O5Cl2 for both forms; the nanorods and nanosheets. Rietveld refinements and crystallite size investigations of the powder patterns revealed significant enhancement in intensity with subtle variation in the lattice parameters and crystallite size decrease in case of nanosheets in comparison to the nanorods assembly. Through scanning electron microscopy, a composition commensurate to Sb4O5Cl2 at% with averaged dimensions; dia.∼90 nm, l ∼ 2 μm for nanorods and dia.∼50–150 nm for nanosheets got corroborated. Owing to the quantum confinement a band gap widening was observed while moving from bulk to nano regime, i.e. 3.25, 3.31 and 3.34 eV, for bulk, nanosheets, and nanorods, respectively. In the case of nanosheets, the highest value of dielectric constant was observed, i.e. 87, as compared to nanorods and the bulk, i.e. 40 and 35.5, respectively. The nanosheets also showed the highest value of dielectric and tangent loss with an increase in frequency due to the least crystallite size of these nanonetworks. Nanosheets depicted the higher AC conductivity at low frequency due to the alignment of the charges but its value decreases at the higher frequency due to lack of time for charge reorientation. The hopping phenomenon was observed in all three cases with the most prominent one in bulk case at higher frequencies. KW - Nanorods KW - Nanosheets KW - Antimony oxychloride ( Sb4O5Cl2) KW - Optical properties KW - Dielectric properties PY - 2019 DO - https://doi.org/10.1088/2053-1591/ab0da9 SN - 2053-1591 VL - 6 IS - 6 SP - 065035 PB - IOP AN - OPUS4-47734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ali, Naveed Zafar A1 - Campbell, B. J. A1 - Jansen, M. T1 - Topotactic, pressure-driven, diffusion-less phasetransition of layered CsCoO2to a stuffedcristobalite-type configuration JF - Acta crystallographica section b-structural science crystal engineering and materials N2 - CsCoO2, featuring a two-dimensional layered architecture of edge- and vertex-linked CoO4tetrahedra, is subjected to a temperature-driven reversible second-order phase transformation at 100 K, which corresponds to a structuralrelaxation with concurrent tilting and breathing modes of edge-sharing CoO4tetrahedra. In the present investigation, it was found that pressure induces a phase transition, which encompasses a dramatic change in the connectivity ofthe tetrahedra. At 923 K and 2 GPa, beta-CsCoO2 undergoes a first-order phasetransition to a new quenchable high-pressure polymorph,alpha-CsCoO2. It is built up of a three-dimensional cristobalite-type network of vertex-sharing CoO4 tetrahedra. According to a Rietveld refinement of high-resolution powderdiffraction data, the new high-pressure polymorph gamma-CsCoO2 crystallizes in the tetragonal space groupI41/amd:2 (Z= 4) with the lattice constants a= 5.8711 (1) and c= 8.3214 (2) A, corresponding to a shrinkage in volume by 5.7% compared with the ambient-temperature and atmospheric pressure-CsCoO2polymorph.The pressure-induced transition (beta>gamma) is reversible;-CsCoO2 stays metastable under ambient conditions, but transforms back to the-CsCoO2structure upon heating to 573 K. The transformation pathway revealed isremarkable in that it is topotactic, as is demonstrated through a clean displacive transformation track between the two phases that employs the symmetry oftheir common subgroupPb21a(alternative setting of space group No. 29 that matches the conventional-phase cell). KW - Structures under extreme conditions KW - Topotactic phase transitions KW - Transformation pathways KW - Oxocobaltates KW - Cristobalite frameworks PY - 2019 DO - https://doi.org/10.1107/S2052520619008436 SN - 2052-5206 VL - 75 IS - 4 SP - 704 EP - 710 PB - International Union of Crystallography AN - OPUS4-48782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aliyah, K. A1 - Prehal, C. A1 - Diercks, J. S. A1 - Diklić, N. A1 - Xu, L. A1 - Ünsal, S. A1 - Appel, C. A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Guizar-Sicairos, M. A1 - Herranz, J. A1 - Gubler, L. A1 - Büchi, F. N. A1 - Eller, J. T1 - Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering JF - ACS Applied Materials & Interfaces N2 - The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode. KW - Polymer electrolyte fuel cell KW - Water management KW - Catalyst layer KW - Representative morphology modeling KW - Small-angle X-ray scattering KW - MOUSE KW - SAXS PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575973 DO - https://doi.org/10.1021/acsami.3c00420 SN - 1944-8244 VL - 15 IS - 22 SP - 26538 EP - 26553 PB - ACS Publications AN - OPUS4-57597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Almalla, A. A1 - Hertwig, Andreas A1 - Fischer, Daniel A1 - Özcan Sandikcioglu, Özlem A1 - Witt, Julia T1 - Development of layer-by-layer assembled thin coatings on aluminium alloy AA2024-T3 for high resolution studies of local corrosion processes JF - Journal of applied polymer science N2 - The aim of this study is to develop nanometer-thin epoxy-based films on aluminium alloy AA2024-T3 as a model coating system for high resolution corrosion studies. Spin coating was used for the layer-by-layer (LbL) deposition of poly-(ethylenimine) (PEI) and poly([o-cresyl glycidyl ether]-co-formaldehyde) (CNER) bilayers. The film chemistry and the cross-linking process were characterized by means of Fourier-transform infrared spectroscopy (FTIR). Ellipsometric data confirmed the linear increase of film thickness. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicate the improvement of the film barrier properties with increasing film thickness. Mapping of the topography and the volta potential was performed by means of scanning Kelvin probe force microscopy (SKPFM). The results indicate the presence of a homogeneous film structure, while the intermetallic phases can still be identified below the coating. The SKPFM Analysis confirmed that the model films are suitable for investigation of corrosion processes at the coating/metal interface. KW - Spectroscopy KW - Coatings KW - Electrochemistry KW - Microscopy KW - Resins PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514627 DO - https://doi.org/10.1002/app.49826 SN - 0021-8995 VL - 137 IS - 48 SP - e49826-1 EP - e49826-9 PB - Wiley CY - New York, NY AN - OPUS4-51462 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 - Altmann, Korinna A1 - Braun, U. A1 - Herper, D. A1 - Knefel, M. A1 - Bednarz, M. A1 - Bannick, C.-G. T1 - Smart filters for the analysis of microplastic in beverages filled in plastic bottles JF - Food Additives & Contaminants: Part A N2 - The occurrence of microplastic (MP) in food products, such as beverages in plastic bottles, is of high public concern. Existing analytical methods focus on the determination of particle numbers, requiring elaborate sampling tools, laboratory infrastructure and generally time-consuming imaging detection methods. A comprehensive routine analysis of MP in food products is still not possible. In the present work, we present the development of a smart filter crucible as sampling and detection tool. After filtration and drying of the filtered-off solids, a direct determination of the MP mass content from the crucible sample can be done by thermal extraction desorption gas chromatography mass spectroscopy (TED-GC/MS). The new filter crucible allows a filtration of MP down to particle sizes of 5 µm. We determined MP contents below 0.01 µg/L up to 2 µg/L, depending on beverages bottle type. This may be directly related to the bottle type, especially the quality of the plastic material of the screw cap. Dependent on the plastic material, particle formation increases due to opening and closing operations during the use phase. However, we have also found that some individual determinations of samples were subjected to high errors due to random events. A conclusive quantitative evaluation of the products is therefore not possible at present. KW - Microplastic KW - TED-GC/MS KW - Plastic bottles KW - Bbeverages KW - Filter crucible PY - 2021 DO - https://doi.org/10.1080/19440049.2021.1889042 SN - 1944-0057 VL - 38 IS - 4 SP - 691 EP - 700 PB - Taylor & Francis AN - OPUS4-52323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Altmann, Korinna A1 - Braun, Ulrike A1 - Bannick, C.-G. A1 - Bednarz, M. A1 - Herper, D. A1 - Knefel, M. T1 - TED-GC/MS: Schnelle Bestimmung von Mikroplastik-Massegehalten in verschiedenen Proben JF - Mitteilungen der GDCh-Fachgruppe Umweltchemie & Ökotoxikologie N2 - Zur Ermittlung von Mikroplastik-Gehalten in verschiedenen Umweltmatrices ist ein schnelles Detektionsverfahren für die Routineanalytik notwendig. Ein solches Verfahren wird hier in Form der ThermoExtraktion/Desorption-GasChromatographie/ MassenSpektroskopie (TED-GC/MS) vorgestellt. Neben grundlegenden verfahrensspezifischen Erläuterungen zur Identifizierung und Quantifizierung von Mikroplastik werden auch exemplarische Beispiele aus unterschiedlichen Umweltkompartimenten und Produkten dargestellt. Neu vorgestellt wird ein neues Verfahren zur Analytik von Flaschenwasser. Dazu wurde ein Messfiltertiegel entwickelt, der besonders für Proben mit geringen Gehalten an abfiltrierbaren Stoffen geeignet ist KW - Mikroplasik KW - Mikroplastik-Analyse KW - TED-GC/MS KW - Thermoanalytische Verfahren KW - Mikroplastik-Massengehalte PY - 2020 VL - 2020 IS - 02 SP - 55 EP - 57 PB - Gesellschaft Deutscher Chemiker (GDCh) CY - Frankfurt am Main AN - OPUS4-50835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Altmann, Korinna A1 - Goedecke, Caroline A1 - Bannick, C.-G. A1 - Abusafia, A. A1 - Scheid, C. A1 - Steinmetz, H. A1 - Paul, Andrea A1 - Beleites, C. A1 - Braun, U. T1 - Identification of microplastic pathways within a typical European urban wastewater system JF - Applied Research N2 - In recent years, thermoextraction/desorption-gas chromatography/mass spectrometry (TED-GC/MS) has been developed as a rapid detection method for the determination of microplastics (MP) mass contents in numerous environmentally relevant matrices and, in particular, for the measurement of polymers in water samples without time-consuming sample preparation. The TED-GC/MS method was applied to investigate a typical European municipal wastewater system for possible MP masses. Such investigations are important in view of the recent revision of the Urban Wastewater Treatment Directive. Four different representative sampling sites were selected: greywater (domestic wastewater without toilet), combined sewer, and influent and effluent of a wastewater treatment plant (WWTP). All samples were collected by fractional filtration. Filtration was carried out over mesh sizes of 500, 100, 50, and in some cases, 5 µm. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were detected in all samples, with the PE fraction dominating in all cases. Styrene-butadiene rubber which serves as an indication of tire abrasion, was only found in the influent of the WWTP. The highest MP mass contents were found in the combined sewer, so MP can become a source of pollution during heavy rain events when the capacity limits of the effluent are reached, and the polluted effluent is released uncontrolled into the environment. Based on the studies, MP retention from the WWTP could be estimated to be approximately 96%. Few trends in polymer type or mass contents were detected within the different fractions of the samples or when comparing samples to each other. KW - Microplastics KW - Microplastic analysis KW - TED-GC/MS KW - Microplastic pathways KW - Mass contents PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568289 DO - https://doi.org/doi.org/10.1002/appl.202200078 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-56828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Altmann, Korinna A1 - Heymann, S. A1 - Braun, U. A1 - Bannick, C.-G. A1 - Heller, C. A1 - Fuchs, M. A1 - Scheid, C. A1 - Abusafia, A. A1 - Steinmetz, H. A1 - Ricking, M. A1 - Kerndorff, A. T1 - Untersuchungsverfahren von Mikroplastikgehalten im Wasser für Praxis und Wissenschaft JF - Korrespondenz Wasserwirtschaft N2 - Zielsetzung des vom Bundesministerium für Bildung und Forschung geförderten Projektes RUSEKU war es, repräsentative Untersuchungsstrategien für die Detektion von Mikroplastik mittels TED GC/MS in wässerigen Medien zu ermitteln. Dabei wurden verschiedene Probenahmekonzepte und – verfahren für unterschiedliche Fallgestaltungen und Fragestellungen untersucht, sowie neue Filtersysteme entwickelt. Bei der Detektion der Partikel lag der Fokus auf der Anwendung und Weiterentwicklung der ThermoExtraktion/Desorption-Gaschromatographie-Massenspektrometrie (TED-GC/MS) zur Bestimmung von Mikroplastikgehalten. Anwendung fanden die Methoden bei der Beprobung von Flaschenwasser, Waschmaschinenabläufen, dem urbanen Abwassersystem der Stadt Kaiserslautern, sowie in Oberflächengewässer. KW - Mikroplastik KW - TED-GC/MS KW - Mikroplastik-Analytik KW - Probennahme PY - 2021 VL - 14. Jahrgang IS - 3 SP - 147 EP - 152 PB - Deutschen Vereinigung für Wasserwirtschaft, Abwasser und Abfall CY - Hennef AN - OPUS4-52260 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Özcan Sandikcioglu, Özlem A1 - Koerdt, Andrea T1 - Iron to Gas: Versatile Multiport Flow-Column Revealed Extremely High Corrosion Potential by Methanogen-Induced Microbiologically Influenced Corrosion (Mi-MIC) JF - Bioleaching and Biocorrosion: Advances in Interfacial Processes N2 - Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows under certain conditions methanogenic archaea can cause higher corrosion than SRB, specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and that spatial statistical evaluations of MIC can be carried out. KW - Microbiologically influenced corrosion KW - Methanogen KW - Methane KW - Biocorrosion KW - Flow system KW - Modeling KW - Multiport PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506084 DO - https://doi.org/10.3389/fmicb.2020.00527 VL - 11 SP - Article 527 PB - Frontiers in microbiology AN - OPUS4-50608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aratsu, K. A1 - Takeya, R. A1 - Pauw, Brian Richard A1 - Hollamby, M.J. A1 - Kitamoto, Y. A1 - Shimizu, N. A1 - Takagi, H. A1 - Haruki, R. A1 - Adachi, S. A1 - Yagai, S. T1 - Supramolecular copolymerization driven by integrative self-sorting of hydrogen-bonded rosettes JF - Nature Communications N2 - Molecular recognition to preorganize noncovalently polymerizable supramolecular complexes is a characteristic process of natural supramolecular polymers, and such recognition processes allow for dynamic self-alteration, yielding complex polymer systems with extraordinarily high efficiency in their targeted function. We herein show an example of such molecular recognition-controlled kinetic assembly/disassembly processes within artificial supramolecular polymer systems using six-membered hydrogen-bonded supramolecular complexes (rosettes). Electron-rich and poor monomers are prepared that kinetically coassemble through a temperature-controlled protocol into amorphous coaggregates comprising a diverse mixture of rosettes. Over days, the electrostatic interaction between two monomers induces an integrative self-sorting of rosettes. While the electron-rich monomer inherently forms toroidal homopolymers, the additional electrostatic interaction that can also guide rosette association allows helicoidal growth of supramolecular copolymers that are comprised of an alternating array of two monomers. Upon heating, the helicoidal copolymers undergo a catastrophic transition into amorphous coaggregates via entropy-driven randomization of the monomers in the rosette. KW - Self-assembly KW - Coaggregation KW - Scattering KW - Simulation KW - AFM PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506555 DO - https://doi.org/10.1038/s41467-020-15422-6 VL - 11 IS - 1 SP - Article number: 1623 PB - Springer Nature AN - OPUS4-50655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aree, T. A1 - McMonagle, C. J. A1 - Michalchuk, Adam A1 - Chernyshov, D. T1 - Low-frequency lattice vibrations from atomic displacement parameters of a-FOX-7, a high energy density material JF - Acta crystallographica B N2 - Highly anharmonic thermal vibrations may serve as a source of structural instabilities resulting in phase transitions, chemical reactions and even the mechanical disintegration of a material. Ab initio calculations model thermal motion within a harmonic or sometimes quasi-harmonic approximation and must be complimented by experimental data on temperature-dependent vibrational frequencies. Here multi-temperature atomic displacement parameters (ADPs), derived from a single-crystal synchrotron diffraction experiment, are used to characterize low-frequency lattice vibrations in the alpha-FOX-7 layered structure. It is shown that despite the limited quality of the data, the extracted frequencies are reasonably close to those derived from inelastic scattering, Raman measurements and density functional theory (DFT) calculations. Vibrational anharmonicity is parameterized by the Grüneisen parameters, which are found to be very different for in-layer and out-of-layer vibrations. KW - Energetic Materials KW - DFT KW - Structural dynamics KW - X-ray diffraction PY - 2022 DO - https://doi.org/10.1107/S2052520622002700 SN - 2052-5206 VL - 78 SP - 376 EP - 384 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-54832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arinchtein, A. A1 - Schnack, R. A1 - Kraffert, K. A1 - Radnik, Jörg A1 - Dietrich, P. A1 - Sachse, René A1 - Krähnert, R. T1 - Role of Water in Phase Transformations and Crystallization of Ferrihydrite and Hematite JF - ACS Applied Materials and Interface N2 - The oxides, hydroxides, and oxo-hydroxides of iron belong to the most abundant materials on earth. They also feature a wide range of practical applications. In many environments, they can undergo facile phase transformations and crystallization processes. Water appears to play a critical role in many of these processes. Despite numerous attempts, the role of water has not been fully revealed yet. We present a new approach to study the influence of water in the crystallization and phase transformations of iron oxides. The approach employs model-type iron oxide films that comprise a defined homogeneous nanostructure. The films are exposed to air containing different amounts of water reaching up to pressures of 10 bar. Ex situ analysis via scanning electron microscopy, Transmission electron microscopy, selected area electron diffraction, and X-ray diffraction is combined with operando near-ambient pressure X-ray photoelectron spectroscopy to follow water-induced changes in hematite nd ferrihydrite. Water proves to be critical for the nucleation of ematite domains in ferrihydrite, the resulting crystallite orientation, and the underlying crystallization mechanism. KW - Iron oxide KW - Ferrihydrite KW - Hematite KW - Water KW - NAP-XPS KW - High pressure PY - 2020 DO - https://doi.org/10.1021/acsami.0c05253 VL - 12 SP - 38714 EP - 38722 PB - ACS Publication AN - OPUS4-51201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - Arnold, M. A1 - Katzmann, J. A1 - Naik, Aakash Ashok A1 - Görne, A. L. A1 - Härtling, Thomas A1 - George, Janine A1 - Schuster, C. T1 - Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: Evidence for and DFT simulation of a radiation-induced phase JF - Journal of materials chemistry C N2 - A recent approach to measure electron radiation doses in the kGy range is the use of phosphors with an irradiation dose-dependent luminescence decay time. However, the applicability of the previously investigated material NaYF4:Yb3+,Er3+ is limited as it shows pronounced fading. Therefore, in this work, a modified SrF2 synthesis is presented that results in SrF2 nanoparticles codoped with Yb and either Er, Hm, or Tm. To assess their suitability as dosimeter material, dose response, as well as its degree of fading over 50 up to 140 days after irradiation were measured. Fading rates as small as 5% in SrF2:Er,Yb and 4% in SrF2:Ho,Yb were derived, which are comparable to established dosimeter materials. A combination of spectroscopy, diffraction and DFT calculations was used to elucidate the effect of irradiation, pointing towards the formation of a secondary phase of Yb2+ that we predict could be Yb2OF2. This irreversible formation of a secondary phase is considered to be the explanation for the low fading behavior in SrF2-based phosphors compared to NaYF4:Yb, Er, a highly attractive feature for electron beam dosimetry. KW - DFT KW - Structure prediction PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554115 DO - https://doi.org/10.1039/D2TC01773C SN - 2050-7526 VL - 10 IS - 32 SP - 11579 EP - 11587 PB - RSC CY - London AN - OPUS4-55411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asadujjaman, Asad A1 - Ahmadi, Vahid A1 - Franc, Antoine Michel Claude A1 - Bertin, Annabelle T1 - 2,6-Diaminopyridine and Acrylamide-Based Copolymers with Upper Critical Solution Temperature-type Behavior in Aqueous Solution JF - Journal of polymer science part a-polymer chemistry N2 - A novel cop olyme r based on supramolecular motif2,6-diaminopyridin e and water-soluble acrylamide, poly[N-(6-ace tamidopyridin-2-yl) acrylamide-co-acrylamide], was synthe-size d via rev ersible addi tion–fragmentation chain transfer (RAFT)polymerization with various monomer compositions. The thermo-respon sive behavior of the copolymers was studied by turbidime-try and dynamic light scattering (DLS). The obtained copolymersshowed an upper critical solution temperature (UCST)-typ e phasetransition behavior in water and electrolyte solution. The phasetransition temperature was found to increase with decreasingam ount of acrylamide in the copolymer and increasing concentra-tion of the solution. Furth ermore, the phase transition temperatureva ried in aqueous solutions of electrolytes according to the naturean d concentration of the electrolyte in accordance with theHoffmeister series. A dramatic solvent isotope effect on thetransition temperature was o bserved in this study, as the transitiontemperature was almost 10–12C higher in D2OthaninH2Oatthesame concentration and acrylamide co mposition. The size of theaggregates below the transition temperature was larger in D2Ocompared to that in H2O that can be explained by deuterium iso-tope effect. The thermoresponsive behavior of the copolymers wasalso investigated in different cell medium and found to be exhibitedUCST-type phase transition behavior in different cell medium.Such behavior of the copo lyme rs can be useful in many a pplica-tions including biomedical, microfluidics, optical materials, and indrug delivery. KW - 2,6-diaminopyridine KW - Acrylamide KW - Stimuli-responsive polymers KW - Thermo-responsive polymers KW - UCST polymers PY - 2019 DO - https://doi.org/10.1002/pola.29474 SN - 0887-624X VL - 57 IS - 19 SP - 2064 EP - 2073 PB - Wiley AN - OPUS4-49297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asadujjaman, Asad A1 - Espinosa de Oliveira, T. A1 - Mukherji, D. A1 - Bertin, Annabelle T1 - Polyacrylamide ‘‘revisited’’: UCST-type reversible thermoresponsive properties in aqueous alcoholic solutions JF - Soft Matter N2 - Combining experiments and all-atom molecular dynamics simulations, we study the conformational behavior of polyacrylamide (PAM) in aqueous alcohol mixtures over a wide range of temperatures. This study Shows that even when the microscopic interaction is dictated by hydrogen bonding, unlike its counterparts that present a lower critical solution temperature (LCST), PAM shows a counterintuitive tunable upper critical solution temperature (UCST)-type phase transition in water/alcohol mixtures that was not reported before. The Phase transition temperature was found to be tunable between 4 and 60 1C by the type and concentration of alcohol in the mixture as well as by the solution concentration and molecular weight of the polymer. In addition, molecular dynamics simulations confirmed a UCST-like behaviour of the PAM in aqueous alcoholic solutions. Additionally, it was observed that the PAM is more swollen in pure alcohol solutions than in 80% alcoholic solutions due to y-like behaviour. Additionally, in the globular state, the size of the aggregates was found to increase with increasing solvent hydrophobicity and polymer concentration of the solutions. Above ist Phase transition temperature, PAM might be present as individual polymer chains in the coil state (r10 nm). As PAM is a widespread polymer in many biomedical applications (gel electrophoresis, etc.), this finding could be of high relevance for many more practical applications in high performance pharmaceuticals and/or sensors. KW - Thermoresponsive polymer KW - UCST-type polymer KW - Polyacrylamide KW - Water/alcohol mixtures PY - 2018 DO - https://doi.org/10.1039/c7sm02424j SN - 1744-6848 SN - 1744-683X VL - 14 IS - 8 SP - 1336 EP - 1343 PB - Royal Society of Chemistry CY - London AN - OPUS4-44002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asanova, T.I. A1 - Asanov, Igor A1 - Yusenko, Kirill A1 - Le Fontane, Camille A1 - Gerasimov, E.Y. A1 - Zadesenetz, A.V. A1 - Korenev, S.V. T1 - Time-resolved study of Pd-Os and Pt-Os nanoalloys formation through thermal decomposition of Pd(NH3)(4) OsCl6 and Pt(NH3)(4) OsCl6 complex salts JF - Materials Research Bulletin N2 - The formation mechanisms of Pd-Os and Pt-Os alloys in the course of thermal decomposition of iso-formular and isostructural complex salts [Pd(NH3)4][OsCl6] and [Pt(NH3)4][OsCl6] in an inert atmosphere have been studied by in-situ QXAFS, XPS and PXRD. The mechanisms of thermal decomposition of the precursors are found to differ from each other, but the detected intermediate products show no significant effect on the local atomic structure around Os, Pt/Pd in their final products. A crystalline beta-trans-[Pd(NH3)2Cl2] intermediate of the first step of thermal decomposition of [Pd(NH3)4][OsCl6] makes the anion [OsCl6]2− transform differently than that of [Pt(NH3)4][OsCl6]. It transforms into a short-lived [Os(NH3)xCl6-x] (2≤x≤4), and then to a distorted octahedron [OsCl6]2−, similar to the high-temperature modification of OsCl4. In case of [Pt(NH3)4][OsCl6], the intermediate [Os(NH3)2Cl4] modifies into four chlorine coordinated Os,{OsCl4}0/1−. Consecutive reduction of Pd(II)/Pt(II) and Os(IV) to the metals defines the homophilic atomic order with the fcc-Pd covered by a random Pd-Os alloy layer and Os on the surface, that is supported by High-Resolution Transmission Electron Mictroscopy (HRTEM) and Scanning TEM (STEM) energy dispersive X-ray (EDX) data, and the diffusion direction going from the surface (hcp-Os) to bulk (fcc-Pd/Pt). As a result, the heterogeneous alloys are formed with a very similar electronic and local atomic structure of Os and Pd/Pt. Upon alloying, the Os 5d5/2,3/2 and Pt 5d5/2,3/2 levels are depleted in the Pt-Os alloys compared to dispersed hcp-Os, fcc-Pt, and Pt foil. This is an unusual behaviour for Os and Pt, calling into question the versatility of d-band theory in bimetallic Os-alloys. The spin-orbit effect at the Os site has been found for both the Pd-Os and Pt-Os alloys, but it is about 4 times less compared to the complex salts. The obtained values for the complex compounds are comparable with those for the iridates, proposed as materials with spin-orbit-induced properties. KW - Thermal decomposition KW - Quick-EXAFS PY - 2021 DO - https://doi.org/10.1016/j.materresbull.2021.111511 VL - 144 SP - 111511 PB - Elsevier Ltd. AN - OPUS4-54010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ayerdi, J. J. A1 - Aginagalde, A. A1 - Llavori, I. A1 - Bonse, Jörn A1 - Spaltmann, Dirk A1 - Zabala, A. T1 - Ball-on-flat linear reciprocating tests: Critical assessment of wear volume determination methods and suggested improvements for ASTM JF - Wear N2 - In the present work it was shown the importance of the correct selection, implementation, and reporting of wear volume computation method and quanitifies the potential errors. KW - Wear KW - Sliding KW - Surface KW - Analysis KW - ASTM KW - D7755-11 PY - 2021 DO - https://doi.org/10.1016/j.wear.2021.203620 VL - 470-471 SP - 3620 AN - OPUS4-52080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Grabowski, Sven A1 - Sahrhage, H. A1 - Lampke, T. T1 - Electrochemical corrosion investigations on binary and ternary zinc alloy coatings using gel electrolytes JF - Advanced engineering materials N2 - Novel agar-based test electrolytes are used to perform electrochemical corrosion investigations on ZnFe and ZnNi binary as well as ZnFeMo ternary zinc coatings. The objectives of the electrochemical investigations include the characterization of the corrosion behavior, the description of the protective effect of the coatings as well as the investigation of the layer formation and degradation under artificial aging. ZnFe and ZnFeMo coatings are applied with varying iron content as well as an additional passivation layer, respectively, to study the effect on corrosion resistance. The results show that the protective effect of the coatings is not negatively influenced by different iron contents or the addition of molybdenum. Additional passivation of the ZnFe-containing coatings by means of a passivating agent leads to a significant improvement in the protective effect. Artificial aging leads to slight degradation of the additional passivation layer whereas coatings without post-treatment enhance their protective effect by the formation of corrosion product layers. KW - Binary zinc alloys KW - Ternary zinc alloys KW - Corrosion testing KW - Gel electrolytes KW - Corrosion PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543013 DO - https://doi.org/10.1002/adem.202101336 SN - 1438-1656 SP - 1 EP - 14 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baek, W. A1 - Gromilov, S. A1 - Kuklin, A. A1 - Kovaleva, E. A1 - Fedorov, A. A1 - Sukhikh, Alex A1 - Hanfland, M. A1 - Pomogaev, V. A1 - Melchakova, Y. A1 - Avramov, P. A1 - Yusenko, Kirill T1 - Unique Nanomechanical Properties of Diamond-Lonsdaleite Biphases: Combined Exp and Theor consideration of popigai impact diamonds JF - Nano Letters N2 - For the first time, lonsdaleite-rich impact diamonds from one of the largest Popigai impact crater (Northern Siberia) with a high concentration of structural defects are investigated under hydrostatic compression up to 25 GPa. It is found that, depending on the nature of a sample, the bulk modulus for lonsdaleite experimentally obtained by X-ray diffraction in diamond-anvil cells is systematically lower and equal to 93.3−100.5% of the average values of the bulk moduli of a diamond matrix. Density functional theory calculations reveal possible coexistence of a number of diamond/lonsdaleite and twin diamond biphases. Among the different mutual configurations, separate inclusions of one lonsdaleite (001) plane per four diamond (111) demonstrate the lowest energy per carbon atom, suggesting a favorable formation of single-layer lonsdaleite (001) fragments inserted in the diamond matrix. Calculated formation energies and experimental diamond (311) and lonsdaleite (331) powder X-ray diffraction patterns indicate that all biphases could be formed under high-temperature, high-pressure conditions. Following the equation of states, the bulk modulus of the diamond (111)/lonsdaleite (001) biphase is the largest one among all bulk moduli, including pristine diamond and lonsdaleite. KW - Compressibility KW - Lonsdaleite KW - Impact diamonds PY - 2019 DO - https://doi.org/10.1021/acs.nanolett.8b04421 VL - 19 IS - 9 SP - 1570 EP - 1576 PB - ACS AN - OPUS4-47403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, D. R. A1 - Karakoti, A. S. A1 - Clifford, C. A. A1 - Minelli, C. A1 - Unger, Wolfgang T1 - Importance of sample preparation on reliable surface characterisation of nano‐objects: ISO standard 20579‐4 JF - Surface and Interface Analysis N2 - The international ISO Standard 20579‐4, dealing with the history and preparation of nano‐objects for surface analysis, has been developed to help address some of the replication and reproducibility issues caused by the fundamental nature of nanoobjects. Although all types of samples requiring surface analysis need thoughtful preparation, nano‐objects, for which many properties are controlled by their surfaces, present additional challenges in order to avoid variations and artefacts due to the handling and preparation of materials prior to analysis. This international standard is part of a series of standards related to preparation of samples for surface chemical analysis. Parts 1 and 2 of ISO Standard series 20579 address general issues that apply to many samples. Part 3, which is still in development, will focus on biomaterials. Part 4 specifically considers issues that arise due to the inherent nature of nano‐objects. Because of sensitivity to their environment, the standard indicates the minimum Information that needs to be reported about the handling and preparation of nano‐objects prior to surface analysis. This information should become part of sample provenance information that helps assure the reliability and usefulness of data obtained from surface‐analysis in the context of the synthesis, processing, and analysis history of a batch of material. Application of this standard can help address reproducibility and traceability issues associated with synthesis, processing, and characterization of nano‐objects in research and commercial applications. KW - Nano‐object characterization KW - Nanoparticle characterization KW - Provenance information KW - Sample preparation KW - Surface analysis PY - 2018 DO - https://doi.org/10.1002/sia.6490 SN - 0142-2421 SN - 1096-9918 VL - 50 IS - 9 SP - 902 EP - 906 PB - John Wiley & Sons, Ltd. AN - OPUS4-45830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baláž, M. A1 - Tešinský, M. A1 - Marquardt, Julien A1 - Škrobian, M. A1 - Daneu, N. A1 - Rajňák, M. A1 - Baláž, P. T1 - Synthesis of copper nanoparticles from refractory sulfides using a semi-industrial mechanochemical approach JF - Advanced Powder Technology N2 - The large-scale mechanochemical reduction of binary sulfides chalcocite (Cu2S) and covellite (CuS) by elemental iron was investigated in this work. The reduction of Cu2S was almost complete after 360 min of milling, whereas in the case of CuS, a significant amount of non-reacted elemental iron could still be identified after 480 min. Upon application of more effective laboratory-scale planetary ball milling, it was possible to reach almost complete reduction of CuS. Longer milling leads to the formation of ternary sulfides and oxidation product, namely cuprospinel CuFe2O4. The rate constant calculated from the magnetometry measurements using a diffusion model for Cu2S and CuS reduction by iron in a large-scale mill is 0.056 min−0.5 and 0.037 min−0.5, respectively, whereas for the CuS reduction in a laboratory-scale mill, it is 0.1477 min−1. The nanocrystalline character of the samples was confirmed by TEM and XRD, as the produced Cu exhibited sizes up to 16 nm in all cases. The process can be easily scaled up and thus copper can be obtained much easier from refractory minerals than in traditional metallurgical approaches. KW - Mechanochemistry KW - Copper sulfides KW - Copper nanoparticles KW - Magnetometry KW - Oxidation PY - 2020 DO - https://doi.org/10.1016/j.apt.2019.11.032 VL - 31 IS - 2 SP - 782 EP - 791 PB - Elsevier B.V. AN - OPUS4-50665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Müller, Patrick A1 - Bertin, Annabelle A1 - Schartel, Bernhard T1 - Hyperbranched Rigid Aromatic Phosphorus-Containing Flame Retardants for Epoxy Resins JF - Macromolecular Materials and Engineering N2 - A rigid aromatic phosphorus-containing hyperbranched flame retardant structure is synthesized from 10-(2,5 dihydroxyphenyl)-10H-9-oxa- 10-phosphaphenanthrene-10-oxide (DOPO-HQ), tris(4-hydroxyphenyl)phosphine oxide (THPPO), and 1,4-terephthaloyl chloride (TPC). The resulting poly-(DOPO-HQ/THPPO-terephthalate) (PDTT) is implemented as a flame retardant into an epoxy resin (EP) at a 10 wt% loading. The effects on EP are compared with those of the monomer DOPO-HQ and triphenylphosphine oxide (OPPh3) as low molar mass flame retardants. The glass transition temperature, thermal decomposition, flammability (reaction to small flame), and burning behavior of the thermosets are investigated using differential scanning calorimetry, thermogravimetric analysis, pyrolysis combustion flow calorimetry, UL 94-burning chamber testing, and cone calorimeter measurements. Although P-contents are low at only 0.6 wt%, the study aims not at attaining V-0, but at presenting a proof of principle: Epoxy resinswith PDTT show promising fire performance, exhibiting a 25% reduction in total heat evolved (THE), a 30% reduction in peak heat release rate (PHRR) due to flame inhibition (21% reduction in effective heat of combustion (EHC)), and an increase in Tg at the same time. This study indicates that rigid aromatic hyperbranched polymeric structures offer a promising route toward multifunctional flame retardancy. KW - Hyperbranched KW - Aromatic KW - Phosphorus KW - Phosphine oxide KW - DOPO KW - Flame retardant KW - Xpoxy resin KW - Rigid PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525910 DO - https://doi.org/10.1002/mame.202000731 SN - 1439-2054 VL - 306 IS - 4 SP - 731 PB - Wiley AN - OPUS4-52591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baumann, Maria A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Wold, C. A1 - Uliyanchenko, E. T1 - Characterization of copolymers of polycarbonate and polydimethylsiloxane by 2D chromatographic separation, MALDI-TOF mass spectrometry, and FTIR spectroscopy JF - International Journal of Polymer Analysis and Characterization N2 - The structure and composition of polycarbonate polydimethylsiloxane copolymer (PC-co-PDMS) was investigated by applying various analytical approaches including chromatographic separation methods, spectrometric, and spectroscopic detection techniques. In particular, size exclusion chromatography (SEC) and liquid adsorption chromatography operating at different conditions (e.g. using gradient solvent systems) were used to achieve separations according to molar mass and functionality distribution. The coupling of both techniques resulted in fingerprint two-dimensional plots, which could be used to easily compare different copolymer batches. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied for structural investigations. The different ionization behavior of both comonomers, however, strongly limited the applicability of this technique. In contrast to that, Fourier-transform Infrared (FTIR) spectroscopy could be used to quantify the amount of PDMS in the copolymer at different points in the chromatogram. The resulting methodology was capable of distinguishing PC-co-PDMS copolymer from PC homopolymer chains present in the material. KW - FTIR KW - Liquid chromatography KW - Mass spectrometry KW - Gradient elution KW - Polycarbonate-co-dimethylsiloxane copolymer PY - 2020 DO - https://doi.org/10.1080/1023666X.2020.1820170 VL - 25 IS - 7 SP - 1 EP - 12 PB - Taylor & Francis AN - OPUS4-51369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bawadkji, O. A1 - Cherri, M. A1 - Schäfer, A. A1 - Herziger, S. A1 - Nickl, Philip A1 - Achazi, K. A1 - Donskyi, Ievgen A1 - Adeli, M. A1 - Haag, R. T1 - One-pot covalent functionalization of 2D black phosphorus by anionic ring opening polymerization JF - Advanced materials interfaces N2 - In this work, a one-pot approach for the covalent functionalization of few-layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP-polyglycerol (BP-PG) with high amphiphilicity for near-infrared-responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP-PG as a promising candidate for a broad range of biomedical applications. KW - 2D nanomaterial KW - Amphiphilicity KW - Black phosphorus KW - Hyperbranched KW - Polyglycerol KW - Water dispersibility PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568833 DO - https://doi.org/10.1002/admi.202201245 SN - 2196-7350 VL - 9 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-56883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Altmann, Korinna A1 - Sommerfeld, Thomas A1 - Braun, Ulrike T1 - Quantification of microplastics in a freshwater suspended organic matter using different thermoanalytical methods – outcome of an interlaboratory comparison JF - Journal of Analytical and Applied Pyrolysis N2 - A sedimented freshwater suspended organic matter fortified with particles of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) was employed in an interlaboratory comparison of thermoanalytical methods for microplastics identification and quantification. Three laboratories performed pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), three others provided results using thermal extraction desorption followed by gas chromatography coupled to mass spectrometry (TED-GC-MS). One participant performed thermogravimetry-infrared spectroscopy (TGA-FTIR) and two participants used thermogravimetry coupled to mass spectrometry (TGA-MS). Further participants used differential scanning microscopy (DSC), a procedure based on micro combustion calorimetry (MCC) and a procedure based on elemental analysis. Each participant employed a different combination of sample treatment, calibration and instrumental Settings for polymer identification and quantification. Though there is obviously room for improvements regarding the between-laboratory reproducibility and the harmonization of procedures it was seen that the participants Performing Py-GC-MS, TED-GC-MS, and TGA-FTIR were able to correctly identify all polymers and to report reasonable quantification results in the investigated concentration range (PE: 20.0 μg/mg, PP: 5.70 μg/mg; PS: 2.20 μg/mg, PET: 18.0 μg/mg). Although for the other methods limitations exists regarding the detection of specific polymers, they showed potential as alternative approaches for polymer quantification in solid environmental matrices. KW - Interlaboratory comparison KW - Microplastics KW - Suspended organic matter KW - Pyrolysis PY - 2020 DO - https://doi.org/10.1016/j.jaap.2020.104829 VL - 148 SP - 1 EP - 6 PB - Elsevier B.V. AN - OPUS4-50977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Scholz, Philipp A1 - Jung, Christian A1 - Weidner, Steffen T1 - Thermo-Desorption Gas Chromatography-Mass Spectrometry for investigating the thermal degradation of polyurethanes JF - Analytical Methods N2 - Thermo-Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to investigate the thermal degradation of two different polyurethanes (PU). PU samples were heated at different heating rates and the desorbed products were collected in a cold injection system and thereafter submitted to GC-MS. Prospects and limitations of the detection and quantification of semi-volatile degradation products were investigated. A temperature dependent PU depolymerization was found at temperatures above 200 °C proved by an increasing release of 1,4-butanediol and methylene diphenyl diisocyanate (MDI) representing the main building blocks of both polymers. Their release was monitored quantitatively based on external calibration with authentic compounds. Size Exclusion Chromatography (SEC) of the residues obtained after thermodesorption confirmed the initial competitive degradation mechanism indicating an equilibrium of crosslinking and depolymerization as previously suggested. Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry of SEC fractions of thermally degraded PUs provided additional hints on degradation mechanism. KW - Thermo-desorption KW - Mass spectrometry KW - Polyurethanes KW - Thermal degradation PY - 2023 DO - https://doi.org/10.1039/D3AY00173C SN - 1759-9660 SP - 1 EP - 6 PB - Royal Society for Chemistry AN - OPUS4-57307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Belenguer, A A1 - Michalchuk, Adam A1 - Lampronti, G A1 - Sanders, J T1 - Using solid catalysts in disulfide-based dynamic combinatorial solution- and mechano-chemistry JF - Chemistry Sustainable Chemistry N2 - We here show for the first time that solid amines can act as catalysts for disulfide-based dynamic combinatorial chemistry by ball mill grinding. The mechanochemical Equilibrium for the two disulfide reactions studied is reached within one to three hours using ten different amine catalysts. This contrasts with the weeks to months to achieve solution equilibrium for most solid amine catalysts at 2%M at 2mM concentration in a suitable solvent. The final mechanochemical equilibrium is independent of the catalyst used, but varies with other ball mill grinding factors such as the presence of traces of solvent. The different efficiencies of the amines tested are discussed. KW - Mechanochemistry KW - Green chemistry KW - Catalysis PY - 2022 DO - https://doi.org/10.1002/cssc.202102416 SN - 1864-5631 VL - 15 IS - 3 SP - 1 EP - 10 PB - Wiley AN - OPUS4-53930 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 - Belenguer, A. A1 - Michalchuk, Adam A1 - Lampronti, G A1 - Sanders, J T1 - Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions JF - Beilstein journal of organic chemistry N2 - We here explore how ball-mill-grinding frequency affects the kinetics of a disulfide exchange reaction. Our kinetic data show that the reaction progress is similar at all the frequencies studied (15–30 Hz), including a significant induction time before the nucleation and growth process starts. This indicates that to start the reaction an initial energy accumulation is necessary. Other than mixing, the energy supplied by the mechanical treatment has two effects: (i) reducing the crystal size and (ii) creating defects in the structure. The crystal-breaking process is likely to be dominant at first becoming less important later in the process when the energy supplied is stored at the molecular level as local crystal defects. This accumulation is taken here to be the rate-determining step. We suggest that the local defects accumulate preferentially at or near the crystal surface. Since the total area increases exponentially when the crystal size is reduced by the crystal-breaking process, this can further explain the exponential dependence of the onset time on the milling frequency. KW - Mechanochemistry KW - Kinetics KW - Diffraction PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483361 DO - https://doi.org/10.3762/bjoc.15.120 SN - 2195-951X VL - 15 SP - 1226 EP - 1235 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-48336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bender, P. A1 - Fock, J. A1 - Hansen, M. F. A1 - Bogart, L. K. A1 - Southern, P. A1 - Ludwig, F. A1 - Wiekhorst, F. A1 - Szczerba, Wojciech A1 - Zeng, L. J. A1 - Heinke, D. A1 - Gehrke, N. A1 - Fernández Díaz, M. T. A1 - González-Alonso, D. A1 - Espeso, J. I. A1 - Rodríguez Fernández, J. A1 - Johansson, C. T1 - Influence of clustering on the magnetic JF - Nanotechnology 29 N2 - Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinTMR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18–56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinTMXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and Relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 105 rad s−1, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FSL, XL, XXL) excel in magnetic hyperthermia experiments. KW - Magnetic hyperthermia KW - Magnetic nanoparticles KW - Multi-core particles KW - Core-clusters PY - 2018 DO - https://doi.org/10.1088/1361-6528/aad67d VL - 29 IS - 42 SP - Articel 425705 PB - IOP Publishing CY - UK AN - OPUS4-47203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Burr, L. A1 - Schmid, D. A1 - Hodoroaba, Vasile-Dan T1 - Towards a method for quantitative evaluation of nanoparticle from suspensions via microarray printing and SEM analysis JF - Journal of Physics: Conference Series N2 - As part of the development of a library of accurate and efficient methods for measurement of nanoparticle properties, we develop and optimize a method for the efficient analysis of nanoparticle size distribution from suspensions via microprinting and digital analysis of electron microscopy (SEM and TEM) images, with the ultimate aim of automated quantitative concentration analysis (calculated from drop volume). A series of different nanoparticle suspensions (gold, latex, and SiO2 in varying sizes and concentrations) were printed onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 nanoparticles/mL and imaged with SEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee-ring effect. KW - Nanoparticles KW - Particle size distribution KW - Electron microscopy KW - Microarray printing KW - Sample preparation KW - Nanoparticle concentration PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528455 DO - https://doi.org/10.1088/1742-6596/1953/1/012002 VL - 1953 SP - 012002 PB - IOP Publishing AN - OPUS4-52845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bennet, Francesca A1 - Müller, Anja A1 - Radnik, Jörg A1 - Hachenberger, Y. A1 - Jungnickel, H. A1 - Laue, P. A1 - Luch, A. A1 - Tentschert, J. T1 - Preparation of Nanoparticles for ToF-SIMS and XPS Analysis JF - Jove-Journal of Visualized Experiments N2 - Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, chemistry, and their potential to enable advanced materials. To effectively understand and regulate the physico-chemical properties and potential adverse effects of nanoparticles, validated measurement procedures for the various properties of nanoparticles need to be developed. While procedures for measuring nanoparticle size and size Distribution are already established, standardized methods for analysis of their surface chemistry are not yet in place, although the influence of the surface chemistry on nanoparticle properties is undisputed. In particular, storage and preparation of nanoparticles for surface analysis strongly influences the analytical results from various methods, and in order to obtain consistent results, sample preparation must be both optimized and standardized. In this contribution, we present, in detail, some standard procedures for preparing nanoparticles for surface analytics. In principle, nanoparticles can be deposited on a suitable substrate from suspension or as a powder. Silicon (Si) Wafers are commonly used as substrate, however, their cleaning is critical to the process. For sample preparation from suspension, we will discuss drop-casting and spin-coating, where not only the cleanliness of the substrate and purity of the suspension but also its concentration play important roles for the success of the preparation methodology. For nanoparticles with sensitive ligand shells or coatings, deposition as powders is more suitable, although this method requires particular care in fixing the sample. KW - Titania nanoparticles KW - X-ray photoelectron spectroscopy KW - Secondary ion mass spectrometry KW - Surface chemisttry PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520103 UR - https://www.jove.com/video/61758 DO - https://doi.org/10.3791/61758 VL - 163 SP - e61758 AN - OPUS4-52010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -