TY - JOUR A1 - Grabolle, Markus A1 - Brehm, Robert A1 - Pauli, Jutta A1 - Dees, F.M. A1 - Hilger, I. A1 - Resch-Genger, Ute T1 - Determination of the labeling density of fluorophore-biomolecule conjugates with absorption spectroscopy N2 - Dye–biomolecule conjugation is frequently accompanied by considerable spectral changes of the dye’s absorption spectrum that limit the use of the common photometrical method for the determination of labeling densities. Here, we describe an improvement of this method using the integral absorbance of the dye instead of its absorbance at the long wavelength maximum to determine the concentration of the biomolecule-coupled dye. This approach is illustrated for three different cyanine dyes conjugated to the antibody IgG. KW - Fluorescent dye KW - Aggregation KW - Dimerization KW - Fluorophore-labeled antibodies KW - Labeling density KW - Dye-to-protein ratio KW - Absorption PY - 2012 DO - https://doi.org/10.1021/bc2003428 SN - 1043-1802 SN - 1520-4812 VL - 23 IS - 2 SP - 287 EP - 292 CY - Washington, DC AN - OPUS4-25527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fleige, E. A1 - Ziem, B. A1 - Grabolle, Markus A1 - Haag, R. A1 - Resch-Genger, Ute T1 - Aggregation phenomena of host and guest upon the loading of dendritic core-multishell nanoparticles with solvatochromic dyes N2 - We systematically assessed the loading behavior of core-multishell nanoparticles (CMS NPs) for the solvatochromic dyes Coumarin 153 and Nile Red and studied the influence of the guest and its concentration on CMS NP aggregation using steady state absorption and fluorescence spectroscopy and dynamic light scattering (DLS). These measurements revealed the strong fluorescence of dye-loaded CMS NPs and formation of nonemissive dye aggregates in the outer CMS layer at higher loading concentrations of Nile Red, whereas in the case of Coumarin 153, a new species with red-shifted absorption and blue-shifted emission appeared. Moreover, dye loading triggers an aggregation of CMS NPs which have a hydrodynamic radius of 8 nm, thereby leading to CMS aggregates with a radius of 100–120 nm. These results underline the need for systematic studies of the influence of the guest and its loading concentration on CMS NP size for cellular uptake and in vivo imaging studies and the rational design of CMS NPs with improved transport and targeting abilities. PY - 2012 DO - https://doi.org/10.1021/ma301977r SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 23 SP - 9452 EP - 9459 PB - American Chemical Society CY - Washington, DC AN - OPUS4-27592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reisgen, U. A1 - Schleser, M. A1 - Abdurakhmanov, A. A1 - Gumenyuk, Andrey T1 - Measuring of plasma properties induced by non-vacuum electron beam welding N2 - Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic. KW - Plasma KW - Diagnostic KW - Welding PY - 2012 DO - https://doi.org/10.1063/1.3675874 SN - 1070-664X VL - 19 SP - 0131006-1 EP - 0131006-7 PB - American Institute of Physics CY - Melville, NY, USA AN - OPUS4-25474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kato, K. A1 - Watanabe, T. A1 - Heine, Hans-Joachim A1 - Boissière, Claudia A1 - Schulz, Gert A1 - Woo, J.-C. A1 - Kim, J.S. A1 - Sang-Hyub, O. A1 - Bae, H. K. A1 - Kim, Y.D. A1 - Qiao, H. A1 - Guenther, F.R. A1 - Roderick, G. C. A1 - Miller, W. A1 - Smeulders, D. A1 - Botha, A. A1 - van Rensburg, M.J. A1 - Tshilongo, J. A1 - Leshabane, N. A1 - Ntsasa, N. A1 - Milton, M. A1 - Vargha, G. A1 - Harling, A. A1 - Konopelko, L. A1 - Kustikov, Y.A. A1 - Vasserman, I.I. A1 - Zavyalov, S. V. A1 - Popova, T.A. A1 - Pankratov, V.V. A1 - Pir, M.N. A1 - Maltsev, M.A. A1 - Oudwater, R. A1 - Persijn, S. A1 - van Wijk, J. A1 - Wessel, R. M. T1 - International comparison CCQM-K66: Impurity analysis of methane N2 - This key comparison was performed to demonstrate the capability of NMIs to analyse the purity of methane for use as a source gas in the preparation of standard gas mixtures. This capability is an essential requirement for the preparation of accurate standards of natural gas and some other fuels. Since it is difficult to carry out a comparison with individual samples of pure gas, the sample for this comparison was a synthetic mixture of high purity methane with selected added impurities of nitrogen, argon, carbon dioxide and ethane. These mixtures were prepared by a gas company as a batch of 10 cylinders and their homogeneity and stability were evaluated by NMIJ. The KCRVs for the four different analytes in this key comparison are based on a consensus of values reported by participants. The uncertainties in the degrees of equivalence were calculated by combining the reported uncertainties with the homogeneity of the samples and the uncertainty of the KCRV. The results submitted are generally consistent with the KCRV within the estimated uncertainties. Finally, this comparison demonstrates that the analysis of nitrogen, argon, carbon dioxide and ethane in methane at amount fractions of 1 µmol/mol to 5 µmol/mol is generally possible with an uncertainty of 5% to 10%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA). DatesIssue 1A (Technical Supplement 2012) KW - Ringversuch KW - Methan KW - Spurenverunreinigungen KW - Gaschromatographie PY - 2012 DO - https://doi.org/10.1088/0026-1394/49/1A/08001 SN - 0026-1394 SN - 1681-7575 VL - 49 IS - 08001 SP - 1 EP - 76 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-25929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the heterogeneously catalyzed partial oxidation of o-xylene in the explosion regime using a microfixed bed reactor N2 - The heterogeneously catalyzed selective gas phase oxidation of o-xylene was investigated, using a microstructured fixed bed reactor, inside of the explosion regime. The reaction was carried out with high amounts of o-xylene in air and stoichiometric with oxygen using a V2O5/TiO2-catalyst prepared through grafting. There were no significant losses in the selectivity to phthalic anhydride observable, during the measurements in the explosion regime, with feed compositions of up to 7 vol% o-xylene. Also the space-time yield was up to 2.3 times higher in comparison to conventional reaction conditions. An increase of the selectivity to total oxidation products was observed at higher o-xylene concentrations between 10 and 25 vol% o-xylene, which possibly was caused by the formation of a hotspot. The investigation of the used catalyst revealed a thermally induced deactivation due to phase transition of anatase into rutil and formation of crystalline vanadium oxide. Despite that expected hotspot at high oxylene concentrations, there was no ignition or explosion of the gas mixture observable. KW - O-xylene oxidation KW - Phthalic anhydride KW - V2O5/TiO2-catalyst KW - Microfixed bed reactor KW - Explosion regime KW - Hotspot PY - 2012 DO - https://doi.org/10.1016/j.ces.2011.10.072 SN - 0009-2509 VL - 69 IS - 1 SP - 440 EP - 448 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-25463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fayis Kalady, Mohammed A1 - Schultz, Johannes A1 - Weinel, Kristina A1 - Wolf, Daniel A1 - Lubk, Axel T1 - Geometry-dependent localization of surface plasmons on random gold nanoparticle assemblies N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered two-dimensional arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope and numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depends on the NP thickness is revealed. Below a NP thickness of 0.4 nm, localization increases toward higher hybridized LSP mode energies. In comparison, above 10 nm thickness, a decrease of localization toward higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a mode energy with minimal localization, is observed. It is shown that this behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs. KW - Gold Nanoparticles KW - Surface plasmons KW - Electron enerdy loss spectroscopy (EELS) KW - scanning transmission electron microscopy PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647230 DO - https://doi.org/10.1103/44nk-6bp2 SN - 2643-1564 VL - 7 IS - 043053 EP - 4 PB - American Physical Society AN - OPUS4-64723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Hans-Joachim A1 - Kipphardt, Heinrich T1 - Application of methane as a gaseous modifier for the determination of silicon using electrothermal atomic absorption spectrometry N2 - For determination of silicon in aqueous solutions by electrothermal atomic absorption spectrometry methane/argon mixtures as a gaseous modifier were applied during the pyrolysis step to improve the analytical performance. The beneficial effects observed on thermal stabilization, signal enhancement and shape of absorbance signals were attributed to the thermal decomposition products of methane, which were hydrogen and carbon black (soot). Using a 5% CH4 mixture with argon, the optimized pyrolysis and atomization temperatures were 1350 °C and 2450 °C, respectively. A flushing step following the pyrolysis was mandatory to avoid background absorption and accelerated deposition of pyrolytic graphite. Characteristic masses of 50 and 30 pg were obtained for standard transversely heated graphite atomizer (THGA) tubes and end-capped THGA tubes, respectively, which were lower than with other previously applied modifiers. A limit of detection of 0.2 µg L- 1 (3 s, n = 10) has been obtained. In addition, this gaseous modifier did not contribute to contamination which often was significant when a liquid modifier solution was co-injected. The proposed method has been applied to the determination of silicon in ultrapure water, nitric and hydrochloric acids. KW - Electrothermal atomic absorption KW - Spectrometry KW - Silicon determination KW - Methane KW - Modifier KW - Ultrapure reagents PY - 2012 DO - https://doi.org/10.1016/j.sab.2012.04.001 SN - 0584-8547 SN - 0038-6987 VL - 70 SP - 68 EP - 73 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-26050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Lange, T. A1 - Klemm, E. T1 - Catalyst as ignition source of an explosion inside a microreactor N2 - The present issue reports on a specific aspect of safety engineering of the heterogeneously catalysed oxidation of ethene in a continuous-flow microreactor. Conversion of ethene and the corresponding surface temperature of the catalyst were monitored for different reactor temperatures and total flow rates with a stoichiometric ethene/oxygen mixture for total oxidation. Safe operation of the highly exothermic oxidation was possible, but not in the whole parameter range. At high reactor temperatures and flow rates, ignition of an explosion inside the microreactor caused by a hot spot on the surface of the catalyst was observed for the first time. KW - Catalyst KW - Ethene KW - Explosions KW - Hot spot KW - Microstructure KW - Safety PY - 2012 DO - https://doi.org/10.1016/j.ces.2012.08.049 SN - 0009-2509 VL - 84 SP - 540 EP - 543 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-26782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hickel, Tilmann A1 - Waske, Anja A1 - Tehranchi, Ali A1 - Bhattacharya, Biswajit A1 - Stawski, Tomasz M. A1 - Fellinger, Tim-Patrick A1 - Mehmood, Asad A1 - Witt, Julia A1 - Ozcan, Ozlem A1 - Guilherme Buzanich, Ana A1 - Kumar, Sourabh A1 - Mishra, Rajesh Kumar A1 - Holzer, Marco A1 - Stucchi de Camargo, Andrea Simone A1 - Agudo Jácome, Leonardo A1 - Manzoni, Anna A1 - Fantin, Andrea A1 - John, Elisabeth A1 - Hodoroaba, Vasile-Dan A1 - Bührig, Sophia A1 - Murugan, Jegatheesan A1 - Marschall, Niklas A1 - George, Janine A1 - Darvishi Kamachali, Reza A1 - Maaß, Robert A1 - Emmerling, Franziska T1 - Chemically complex materials enable sustainable high-performance materials N2 - Chemically complex materials (CCMats) 􀀀 including high-entropy alloys, oxides, and related multi-principal element systems 􀀀 offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility. Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and environmental demands. KW - Chemically complex materials KW - Structural stability KW - Functional performance KW - Design strategies KW - Sustainability PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655598 UR - https://www.sciencedirect.com/science/article/pii/S1359028626000033?via%3Dihub DO - https://doi.org/10.1016/j.cossms.2026.101256 SN - 1359-0286 VL - 42 SP - 1 EP - 26 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-65559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harrer, Andrea A1 - Daschewski, Maxim A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Guderian, Matthias A1 - Meyer-Plath, Asmus T1 - Thermoacoustic generation of airborne ultrasound using carbon materials at the micro- and nanoscale N2 - The generation of airborne ultrasound is presented using the thermoacoustic principle applied to carbon materials at the micro- and nanoscale. Such materials are shown to be capable of emitting ultrasound when being fed by an alternating current. We tested the acoustic performance of carbon fibers, bucky papers and electrospun polyacrylonitrile-derived carbon nanofibers and determined the sound pressure for frequencies up to 350 kHz. A comparison between the experimental results and the theoretical prediction showed remarkable agreement for frequencies up to 150 kHz. Beyond 150 kHz, we found slight deviations from the expected sound pressure dependence on the square root of the frequency. KW - Thermoacoustic KW - Airborne ultrasound transducer KW - Sound pressure PY - 2012 DO - https://doi.org/10.3233/JAE-2012-1440 SN - 1383-5416 SN - 0925-2096 VL - 39 IS - 1-4 SP - 35 EP - 41 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-26737 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gravenkamp, Hauke A1 - Song, C. A1 - Prager, Jens T1 - A numerical approach for the computation of dispersion relations for plate structures using the scaled boundary finite element method N2 - In this paper, a method is presented for the numerical computation of dispersion properties and mode shapes of guided waves in plate structures. The formulation is based on the Scaled Boundary Finite Element Method. The through-thickness direction of the plate is discretized in the finite element sense, while the direction of propagation is described analytically. This leads to a standard eigenvalue problem for the calculation of wave numbers. The proposed method is not limited to homogeneous plates. Multi-layered composites as well as structures with continuously varying material parameters in the direction of thickness can be modeled without essential changes in the formulation. Higher-order elements have been employed for the finite element discretization, leading to excellent convergence for complex structures. It is shown by numerical examples that this method provides highly accurate results with a small number of nodes while avoiding numerical problems and instabilities. KW - Scaled boundary finite element method KW - Lamb waves KW - Dispersion KW - Non-destructive testing KW - Composites KW - Functionally graded materials PY - 2012 DO - https://doi.org/10.1016/j.jsv.2012.01.029 SN - 0022-460X SN - 1095-8568 VL - 331 IS - 11 SP - 2543 EP - 2557 PB - Academic Press CY - London AN - OPUS4-25743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gravenkamp, Hauke A1 - Prager, Jens A1 - Saputra, A. A. A1 - Song, C. T1 - The simulation of Lamb waves in a cracked plate using the scaled boundary finite element method N2 - The scaled boundary finite element method is applied to the simulation of Lamb waves for ultrasonic testing applications. With this method, the general elastodynamic problem is solved, while only the boundary of the domain under consideration has to be discretized. The reflection of the fundamental Lamb wave modes from cracks of different geometry in a steel plate is modeled. A test problem is compared with commercial finite element software, showing the efficiency and convergence of the scaled boundary finite element method. A special formulation of this method is utilized to calculate dispersion relations for plate structures. For the discretization of the boundary, higher-order elements are employed to improve the efficiency of the simulations. The simplicity of mesh generation of a cracked plate for a scaled boundary finite element analysis is illustrated. KW - Lamb waves KW - Scaled boundary finite element method KW - Dispersion KW - Structural dynamics KW - Cracks PY - 2012 DO - https://doi.org/10.1121/1.4740478 SN - 0001-4966 SN - 1520-8524 VL - 132 IS - 3 SP - 1358 EP - 1367 PB - AIP CY - Melville, NY, USA AN - OPUS4-27115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hanelt, Sven A1 - Friedrich, Jörg Florian A1 - Orts Gil, Guillermo A1 - Meyer-Plath, Asmus T1 - Study of Lewis acid catalyzed chemical bromination and bromoalkylation of multi-walled carbon nanotubes N2 - Chemical functionalization of carbon nanotubes (CNT) with nucleophiles requires introduction of electrophilic reactive sites on the CNTs. This can, for instance, be accomplished by the chemical bromination procedure with elemental bromine and a set of Lewis acids (BBr3, BF3 × Et2O, AlBr3, FeBr3, ZnBr2, TiBr4, SiBr4, SnBr4, VBr3) or a radical starter like dibenzoylperoxide (DBPO) in appropriate solvents at varied temperature. The present approach to electrophilic sites relies on the well-known electrophilic aromatic substitution or addition of bromine with aromatic structural units. In addition to the use of bromine, the introduction of haloalkyl groups was also investigated here using bis-electrophiles or haloalcohols and Brønsted acids. The advantages and drawbacks of the studied reaction conditions, the obtained degree of bromination as analyzed by X-ray photoelectron spectroscopy (XPS) and the amount of introduced bromine that can be substituted by a nucleophile are presented and discussed. KW - Carbon nanotubes KW - Bromierung KW - Lewis Säure KW - Bromalkylierung KW - CNT PY - 2012 DO - https://doi.org/10.1016/j.carbon.2011.11.009 SN - 0008-6223 SN - 1873-3891 VL - 50 IS - 3 SP - 1373 EP - 1385 PB - Pergamon Press CY - New York, NY AN - OPUS4-25207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günzel, Stephan A1 - Hickmann, Stefan A1 - Wittemeyer, Christian A1 - Trappe, Volker T1 - Effects of fiber orientation and moisture on the crack growth in short glass fiber reinforced polyamide N2 - Short glass fiber reinforced polyamides are increasingly used in automotive applications. Concepts and models are needed, which enable the prediction of the structural durability. The fiber orientation and the content of moisture have a major influence on the fracture mechanical properties and on the damage mechanisms. The complex crack growth behavior was investigated and described in an empirical model. PY - 2012 DO - https://doi.org/10.1002/adem.201100337 SN - 1438-1656 VL - 14 IS - 10 SP - 867 EP - 872 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-26938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henning, Thorsten A1 - Goerdeler, Cornelius A1 - El-Khatib, Ahmed H. A1 - Meyer, Klas A1 - Bruer, Gustav G. A1 - Abraham, Klaus A1 - Monien, Bernhard T1 - Characterization and quantitation of urinary metabolites of 3-monochloropropane-1,2-diol (3-MCPD) in rats N2 - Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD) are heat-induced contaminants formed from fats and sodium chloride. The mode of action for the 3-MCPD mediated induction of renal tubule neoplasms in rats is still unclear, which is in part due to lacking metabolism data. In the current study, urinary metabolites were identified by one- and two-dimensional 13C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry following oral administration of 3-MCPD or [13C3]3-MCPD in rats. In addition to 3-MCPD itself, nine metabolites were identified. Four of those, N-acetyl-S-(2,3-dihydroxypropyl)cysteine (DHPMA), 3-MCPD sulfate, β-chlorolactic acid (β-ClLA) and oxalic acid have been reported before. Five novel metabolites in rat urine were thiodiglycolic acid (TDGA), thionyldiglycolic acid (TNDGA), 3-MCPD glucuronide (at least three isomers), 3-carboxy-2-hydroxypropyl mercapturic acid (CHPMA), and 3-(S-carboxymethyl)mercaptolactic acid (CMMLA). Only three metabolites were excreted at mean dose ratios > 1% (after treatment with 50 mg 3-MCPD/kg body weight in male and female rats), i.e. 3-MCPD (7.3%, 9.7%), DHPMA (3.5%, 1.7%) and TDGA (1.1%, 4.0%). The overall mean dose excretion in urine samples (males: 12.2%, females: 16.3%) supported hypotheses on formation of conjugates/adducts of reactive metabolites and the possibility that dechlorination leads to suitable building blocks for amino acid and fatty acid synthesis. The identification of TDGA indicated the interim formation 2-chloroacetaldehyde, previously identified to mediate specific nephrotoxic effects of the cytostatic ifosfamide in rats. KW - 3-Monochloropropane-1,2-diol KW - 3-MCPD KW - Metabolism KW - Urine PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657230 DO - https://doi.org/10.1007/s00204-026-04318-x SP - 1 EP - 17 PB - Springer-Verlag GmbH CY - Heidelberg AN - OPUS4-65723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battistella, Beatrice A1 - Revill, Adam A1 - Venzago, Cornel A1 - Hoffmann, Volker A1 - Agudo Jácome, Leonardo A1 - Al-Sabbagh, Dominik A1 - Recknagel, Sebastian A1 - Abad, Carlos T1 - Depth-Resolved Lithium Isotope Fractionation as a Diagnostic of Interphase Evolution and Degradation in Lithium-Ion Batteries N2 - Lithium isotopic fractionation is well-established in dynamic geochemical systems; however, its role in lithium-ion batteries (LIBs) remains uninvestigated. Herein, we report the first depth-resolved demonstration that isotopic separation occurs during Li-ion cell operation whose magnitude depends on the cycling history. Using depth-resolved glow discharge mass spectrometry, we monitored the 7Li/6Li ratio in LiNi0.333Mn0.333Co0.333O2 (NMC111)||graphite coin cell electrodes at defined life-cycle stages. Different charging rates were examined to get mechanistic insight into kinetic and thermodynamic control in the fractionation process. Although pristine electrodes exhibit a uniform isotopic ratio, cycled electrodes show a distinct 7Li enrichment in the positive electrode and a corresponding accumulation of 6Li at the surface of the negative electrode. The degree of isotopic separation varies with the charging rate. Isotopic signatures correlate with capacity fading, indicating lithium isotope mapping as a sensitive diagnostic tool for tracking electrode degradation and the evolution of the electrode–electrolyte interphases in LIBs. KW - Lithium-Ion Battery KW - Li Isotopes KW - Glow Discharge Mass Spectrometry GD-MS PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657229 DO - https://doi.org/10.1021/acsenergylett.5c0413737 SN - 2380-8195 VL - 11 IS - 3 SP - 2851 EP - 2857 PB - ACS Publications AN - OPUS4-65722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zink, N. A1 - Emmerling, Franziska A1 - Häger, T. A1 - Panthöfer, M. A1 - Tahir, M.N. A1 - Kolb, U. A1 - Tremel, W. T1 - Low temperature synthesis of monodisperse nanoscaled ZrO2 with a large specific surface area N2 - Thermal decomposition of Zr(C2O4)2·4H2O within an autoclave or in a conventional tube furnace at temperatures below 380 °C resulted in nano- and micron-sized ZrO2, respectively. Reactions under autogenic pressure yielded monodisperse monoclinic (m) and tetragonal (t) ZrO2 nanoparticles with an average diameter of ~8 nm and interconnected t-ZrO2 nanoparticles with diameters of ~4 nm, depending on the synthesis temperature. Samples were characterised by X-ray diffraction (XRD), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) associated with energy dispersive X-ray spectroscopy (EDS), Raman microspectroscopy and photoluminescence spectroscopy (PL). Nanostructured zirconia materials exhibited high specific areas of 276–385 m2 g-1 which make them promising candidates as catalysts and catalyst supports. Co-existence of m- and t-ZrO2 nanoparticles with diameters of 6–9 nm, i.e. above the critical particle size of 6 nm for the formation of t-ZrO2, demonstrated that the particle size is not the only factor for stabilisation of the t-ZrO2 modification at room temperature. PY - 2013 DO - https://doi.org/10.1039/c2dt12496c SN - 1477-9226 SN - 1477-9234 SN - 1364-5447 VL - 42 SP - 432 EP - 440 PB - RSC CY - Cambridge AN - OPUS4-27733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mönch, Bettina A1 - Emmerling, Franziska A1 - Kraus, Werner A1 - Becker, Roland A1 - Nehls, Irene T1 - Isopropyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside N2 - The title compound, C17H26O10, was formed by a Koenigs-Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide and propan-2-ol. The central ring adopts a chair conformation. The crystal does not contain any significant intermolecular interactions. PY - 2013 DO - https://doi.org/10.1107/S1600536812051483 SN - 1600-5368 VL - 69 IS - Part 2 SP - o157, sup-1 - sup-7 PB - Munksgaard CY - Copenhagen AN - OPUS4-27572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppen, Robert A1 - Emmerling, Franziska A1 - Koch, Matthias T1 - rac-2,3-Dibromopropionamide N2 - The racemic title compound, C3H5Br2NO, was crystallized from methanol. In the crystal, adjacent molecules are linked through N–H···O hydrogen bonds, forming chains along the c-axis direction. These chains are linked through N–H···O hydrogen bonds, forming an undulating two-dimensional network lying parallel to the bc plane. There are also short Br···Br contacts present [3.514 (3) Å]. PY - 2013 DO - https://doi.org/10.1107/S160053681205132X SN - 1600-5368 VL - 69 IS - Part 2 SP - o151, sup-1 EP - sup-5 PB - Munksgaard CY - Copenhagen AN - OPUS4-27574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simo, A. A1 - Polte, Jörg A1 - Pfänder, N. A1 - Vainio, U. A1 - Emmerling, Franziska A1 - Rademann, K. T1 - Formation mechanism of silver nanoparticles stabilized in glassy matrices N2 - In any given matrix control over the final particle size distribution requires a constitutive understanding of the mechanisms and kinetics of the particle evolution. In this contribution we report on the formation mechanism of silver nanoparticles embedded in a soda-lime silicate glass matrix. For the silver ion-exchanged glass it is shown that at temperatures below 410 °C only molecular clusters (diameter <1 nm) are forming which are most likely silver dimers. These clusters grow to nanoparticles (diameter >1 nm) by annealing above this threshold temperature of 410 °C. It is evidenced that the growth and thus the final silver nanoparticle size are determined by matrix-assisted reduction mechanisms. As a consequence, particle growth proceeds after the initial formation of stable clusters by addition of silver monomers which diffuse from the glass matrix. This is in contrast to the widely accepted concept of particle growth in metal–glass systems, in which it is assumed that the nanoparticle formation is predominantly governed by Ostwald ripening processes. PY - 2012 DO - https://doi.org/10.1021/ja309034n SN - 0002-7863 SN - 1520-5126 VL - 134 IS - 45 SP - 18824 EP - 18833 PB - American Chemical Society CY - Washington, DC AN - OPUS4-27539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gnutzmann, Tanja A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Fast crystallization of organic glass formers N2 - An unusually fast crystallization of the organic glass former nifedipine has been observed. The crystallization process, starting from an amorphous film to crystalline material, was investigated by time resolved Raman microspectroscopy. The crystallization rates of the initially crystallizing metastable β-form are four orders of magnitude higher than those of previous studies. KW - Polymorphism KW - Raman spectroscopy KW - Crystallization KW - Nifedipine PY - 2012 DO - https://doi.org/10.1039/c1cc16301a SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 48 SP - 1638 EP - 1640 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-27735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Comba, P. A1 - Emmerling, Franziska A1 - Jakob, M. A1 - Kraus, Werner A1 - Kubeil, M. A1 - Morgen, M. A1 - Pietzsch, J. A1 - Stephan, H. T1 - Copper(II) chemistry of the functionalized macrocycle cyclam tetrapropionic acid N2 - The CuII complex of H4TETP (H4TETP = 1,4,8,11-tetraazatetradecane-1,4,8,11-tetrapropionic acid) is five-coordinate with a distorted square-pyramidal structure (τ = 0.45; i.e. the geometry is nearly half-way between square-pyramidal and trigonal-bipyramidal) and a relatively long Cu–N and a short Cu–O bond; the comparison between powder and solution electronic spectroscopy, the frozen solution EPR spectrum and ligand-field-based calculations (angular overlap model, AOM) indicate that the solution and solid state structures are very similar, i.e. the complex has a relatively low 'in-plane' and a significant axial ligand field with a dx²-y² ground state. The ligand-enforced structure is therefore shown to lead to a partially quenched Jahn–Teller distortion and to a relatively low complex stability, lower than with the corresponding acetate-derived ligand H4TETA. This is confirmed by potentiometric titration and by the biodistribution with 64Cu-labeled ligands which show that the uptake in the liver is significantly increased with the H4TETP-based system. KW - Copper(II) KW - Chemistry PY - 2013 DO - https://doi.org/10.1039/c2dt32356g SN - 1477-9226 SN - 1477-9234 SN - 1364-5447 VL - 42 IS - 17 SP - 6142 EP - 6148 PB - RSC CY - Cambridge AN - OPUS4-28075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gnutzmann, Tanja A1 - Kahlau, R. A1 - Scheifler, S. A1 - Friedrichs, Ferdinand A1 - Rössler, A. A1 - Rademann, Klaus A1 - Emmerling, Franziska T1 - Crystal growth rates and molecular dynamics of nifedipine N2 - The unusually fast crystallization of the organic compound nifedipine has been investigated in detail using different solutions as precursors for the formation of the initial glassy nifedipine films. Starting from these amorphous films the crystallization process was investigated by time-resolved light microscopy at different temperatures around Tg of nifedipine. In all studied cases (acetone, acetonitrile, ethyl acetate, dichloromethane, tetrahydrofuran) the measured mean crystallization rates are, on average, 10000 times higher than rates reported in previous studies. Such high rates cannot be explained by a classical diffusional crystal growth mechanism of nifedipine. Instead, nifedipine shows a strong propensity for diffusionless growth. Solvent assisted or solvent induced preordering of the glassy modification is suggested to be the most probable driving force behind these fast crystallization processes. The nifedipine crystallization rates can be controlled not only by specific solvent–molecule interactions but also by temperature. Below 40 °C, the temperature dependence of the rates is generally small. Above 40 °C, a slowing down of the crystallization rates with increasing temperatures indicates a kinetic competition between different polymorphs. The molecular dynamics of nifedipine molecules in the amorphous phase as well as the relaxation times are studied by dielectric measurements. The dielectric data corroborate the inherently strong propensity of nifedipine to crystallize diffusionlessly under all conditions. KW - Fast crystallization KW - Diffusionless growth KW - Polymorphism KW - Nifedipine KW - Preordering KW - Raman spectroscopy KW - Dielectric spectroscopy PY - 2013 DO - https://doi.org/10.1039/c2ce26911b SN - 1466-8033 VL - 15 IS - 20 SP - 4017 EP - 4202 CY - London, UK AN - OPUS4-28307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, C. A1 - Takao, S. A1 - Takao, K. A1 - Weiss, s. A1 - Kraus, Werner A1 - Emmerling, Franziska A1 - Meyer, M. A1 - Scheinost, A.C. T1 - Identification of hexanuclear actinide(IV) carboxylates with thorium, uranium and neptunium by EXAFS spectroscopy N2 - Hydrated actinide(IV) ions undergo hydrolysis and further polymerization and precipitation with increasing pH. The resulting amorphous and partly crystalline oxydydroxides AnOn(OH)4-2n·xH2O can usually be observed as colloids above the An(IV) solubility limit. The aging process of such colloids results in crystalline AnO2. The presence of carboxylates in the solution prevents the occurrence of such colloids by formation of polynuclear complexes through a competing reaction between hydrolysis and ligation. The majority of recently described carboxylates reveals a hexanuclear core of [An6(µ3-O)4(µ3-OH)4]12+ terminated by 12 carboxylate ligands. We found that the An(IV) carboxylate solution species remain often preserved in crystalline state. The An(IV) carboxylates show An–An distances which are ~ 0.03 Å shorter than the An–An distances in AnO2 like colloids. The difference in the distances could be used to identify such species in solution. T2 - XAFS15 - 15th International conference on X-ray absorption fine structure CY - Beijing, China DA - 22.07.2012 KW - Carboxylates KW - EXAFS KW - Actinide PY - 2013 DO - https://doi.org/10.1088/1742-6596/430/1/012116 SN - 1742-6588 SN - 1742-6596 VL - 430 SP - 012116-1 EP - 012116-5 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-28525 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Som, Tirtha A1 - Troppenz, G.V. A1 - Wendt, R. R. A1 - Wollgarten, M. A1 - Rappich, J. A1 - Emmerling, Franziska A1 - Rademann, Klaus T1 - Graphene oxide/alpha-Bi2O3 composites for visible-light photocatalysis, chemical catalysis, and solar energy conversion N2 - The growing challenges of environmental purification by solar photocatalysis, precious-metal-free catalysis, and photocurrent generation in photovoltaic cells receive the utmost global attention. Here we demonstrate a one-pot, green chemical synthesis of a new stable heterostructured, ecofriendly, multifunctional microcomposite that consists of α-Bi2O3 microneedles intercalated with anchored graphene oxide (GO) microsheets (1.0 wt?%) for the above-mentioned applications on a large economical scale. The bare α-Bi2O3 microneedles display two times better photocatalytic activities than commercial TiO2 (Degussa-P25), whereas the GO-hybridized composite exhibits approximately four to six times enhanced photocatalytic activities than the neat TiO2 photocatalyst in the degradation of colored aromatic organic dyes (crystal violet and rhodamine 6G) under visible-light irradiation (300 W tungsten lamp). The highly efficient activity is associated with the strong surface adsorption ability of GO for aromatic dye molecules, the high carrier acceptability, and the efficient electron–hole pair separation in Bi2O3 by individual adjoining GO sheets. The introduction of Ag nanoparticles (2.0 wt?%) further enhances the photocatalytic performance of the composite over eightfold because of a plasmon-induced electron-transfer process from Ag nanoparticles through the GO sheets into the conduction band of Bi2O3. The new composites are also catalytically active and catalyze the reduction of 4-nitrophenol to 4-aminophenol in the presence of borohydride ions. Photoanodes assembled from GO/α-Bi2O3 and Ag/GO/α-Bi2O3 composites display an improved photocurrent response (power conversion efficiency ~20?% higher) over those prepared without GO in dye-sensitized solar cells. KW - Bismuth KW - Dyes/pigments KW - Environmental chemistry KW - Graphene KW - Photochemistry PY - 2014 DO - https://doi.org/10.1002/cssc.201300990 SN - 1864-5631 SN - 1864-564X VL - 7 IS - 3 SP - 854 EP - 865 PB - Wiley-VCH CY - Weinheim AN - OPUS4-30390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balski, Matthias A1 - Emmerling, Franziska A1 - Kipphardt, Heinrich A1 - Panne, Ulrich T1 - Determination of boron in silicon without use of additional complexing agents N2 - Methods for the determination of boron in various matrices described in the literature usually employ complexing agents like mannitol to retain the volatile boron species during matrix evaporation steps. However, also relatively high boron recoveries from silicon containing samples have been reported when no complexing agents were added to the digestion acids. The mechanism behind this matrix-dependant recovery has been investigated by studying the boron recovery in the analysis of solar grade silicon. It was found that the NH4+ ion formed by the reduction of nitric acid during sample digestion is responsible for the higher recovery of boron, which leads to a possible analysis method without the use of complexing agents if the sample preparation procedure is carefully optimized. KW - Boron KW - Complexing agents KW - Matrix evaporation KW - Sample enrichment PY - 2014 DO - https://doi.org/10.1039/c4ay00410h SN - 1759-9660 SN - 1759-9679 VL - 6 IS - 12 SP - 4003 EP - 4008 PB - RSC Publ. CY - Cambridge AN - OPUS4-30956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lauer, Franziska A1 - Diehn, Sabrina A1 - Seifert, Stephan A1 - Kneipp, Janina A1 - Sauerland, V. A1 - Barahona, C. A1 - Weidner, Steffen T1 - Multivariate analysis of MALDI imaging mass spectrometry data of mixtures of single pollen grains N2 - Mixtures of pollen grains of three different species (Corylus avellana, Alnus cordata, and Pinus sylvestris) were investigated by matrixassisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF imaging MS). The amount of pollen grains was reduced stepwise from > 10 to single pollen grains. For sample pretreatment, we modified a previously applied approach, where any additional extraction steps were omitted. Our results show that characteristic pollen MALDI mass spectra can be obtained from a single pollen grain, which is the prerequisite for a reliable pollen classification in practical applications. MALDI imaging of laterally resolved pollen grains provides additional information by reducing the complexity of the MS spectra of mixtures, where frequently peak discrimination is observed. Combined with multivariate statistical analyses, such as principal component analysis (PCA), our approach offers the chance for a fast and reliable identification of individual pollen grains by mass spectrometry. KW - MALDI Imaging MS KW - Pollen grains KW - Multivariate Statistics KW - Hierarchical cluster analysis KW - Principal component analysis PY - 2018 DO - https://doi.org/10.1007/s13361-018-2036-5 SN - 1044-0305 SN - 1879-1123 VL - 29 IS - 11 SP - 2237 EP - 2247 PB - Springer AN - OPUS4-45607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Döring, Sarah A1 - Wulfes, Birte S. A1 - Atanasova, Aleksandra A1 - Jaeger, Carsten A1 - Walzel, Leopold A1 - Tscheuschner, Georg A1 - Flemig, Sabine A1 - Gawlitza, Kornelia A1 - Feldmann, Ines A1 - Konthur, Zoltán A1 - Weller, Michael G. T1 - Corundum Particles as Trypsin Carrier for Efficient Protein Digestion N2 - Reusable enzyme carriers are valuable for proteomic workflows, yet many supports are expensive or lack robustness. This study describes the covalent immobilization of recombinant trypsin on micrometer-sized corundum particles and assesses their performance in protein digestion and antibody analysis. The corundum surface was cleaned with potassium hydroxide, silanized with 3-aminopropyltriethoxysilane and activated with glutaraldehyde. Recombinant trypsin was then attached, and the resulting imines were reduced with sodium cyanoborohydride. Aromatic amino acid analysis (AAAA) estimated an enzyme loading of approximately 1 µg/mg. Non-specific adsorption of human plasma proteins was suppressed by blocking residual aldehydes with a Tris-glycine-lysine buffer. Compared with free trypsin, immobilization shifted the temperature optimum from 50 to 60 °C and greatly improved stability in 1 M guanidinium hydrochloride. Activity remained above 80% across several reuse cycles, and storage at 4 °C preserved functionality for weeks. When applied to digesting the NISTmAb, immobilized trypsin provided peptide yields and sequence coverage comparable to soluble enzyme and outperformed it at elevated temperatures. MALDI-TOF MS analysis of Herceptin digests yielded fingerprint spectra that correctly identified the antibody and achieved 60% sequence coverage. The combination of low cost, robustness and analytical performance makes corundum-immobilized trypsin an attractive option for research and routine proteomic workflows. N2 - Wiederverwendbare Enzymcarrier sind für proteomische Arbeitsabläufe von großem Wert, doch viele Trägermaterialien sind teuer oder nicht robust genug. Diese Studie beschreibt die kovalente Immobilisierung von rekombinantem Trypsin auf mikrometergroßen Korundpartikeln und bewertet deren Leistungsfähigkeit beim Proteinverdau und der Antikörperanalyse. Die Korundoberfläche wurde mit Kaliumhydroxid gereinigt, mit 3-Aminopropyltriethoxysilan silanisiert und mit Glutaraldehyd aktiviert. Anschließend wurde rekombinantes Trypsin gebunden, und die entstandenen Imine wurden mit Natriumcyanoborhydrid reduziert. Die aromatische Aminosäureanalyse (AAAA) ergab eine geschätzte Enzymbeladung von etwa 1 µg/mg. Die unspezifische Adsorption von menschlichen Plasmaproteinen wurde durch Blockierung der restlichen Aldehyde mit einem Tris-Glycin-Lysin-Puffer unterdrückt. Im Vergleich zu freiem Trypsin verschob die Immobilisierung das Temperaturoptimum von 50 auf 60 °C und verbesserte die Stabilität in 1 M Guanidiniumhydrochlorid erheblich. Die Aktivität blieb über mehrere Wiederverwendungszyklen hinweg bei über 80 %, und die Lagerung bei 4 °C bewahrte die Funktionalität über Wochen hinweg. Beim Verdau des NISTmAb lieferte das immobilisierte Trypsin Peptidausbeuten und Sequenzabdeckungen, die mit denen des löslichen Enzyms vergleichbar waren, und übertraf dieses bei erhöhten Temperaturen. Die MALDI-TOF-MS-Analyse von Herceptin-Verdauen ergab Fingerabdruck-Spektren, die den Antikörper korrekt identifizierten und eine Sequenzabdeckung von 60 % erreichten. Die Kombination aus niedrigen Kosten, Robustheit und analytischer Leistungsfähigkeit macht auf Korund immobilisiertes Trypsin zu einer attraktiven Option für die Forschung und routinemäßige proteomische Arbeitsabläufe. KW - Bottom-up proteomics KW - Solid-phase digestion KW - Biopharmaceutical analysis KW - Peptide mapping KW - Non-specific binding KW - amino acid analysis PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657021 DO - https://doi.org/10.3390/biotech15010002 SN - 2673-6284 VL - 15 IS - 1 SP - 1 EP - 23 PB - MDPI CY - Basel AN - OPUS4-65702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mehri Sofiani, F. A1 - Chaudhuri, Somsubhro A1 - Elahi, S. A. A1 - Wallaert, E. A1 - Depover, T. A1 - De Waele, W. T1 - Accelerated laboratory simulation of corrosion pit evolution in low-carbon steel using phase-field guided overpotential application N2 - This study is performed to replicate field data of pit geometry evolution in the laboratory by accelerating pit evolution through the application of relatively high overpotential on low-carbon steel. A phase-field model is used to reduce the number of trials and errors in the laboratory. The effect of overpotential on pitting corrosion is studied in low-carbon steel in the electrolyte representative of the North Sea. Based on the results obtained through the numerical model, potentiostatic polarisation tests are performed, and a comparison is made between such accelerated tests and steel coupons collected from the field. The results of this comparison suggest that the pitting corrosion acceleration mechanism effectively produces surface conditions closely resembling those of naturally pitted steel. Additionally, it enables the investigation of the electrochemical characteristics of a stable pit over long-term exposure, where direct probing is challenging. This framework strives to mitigate the excessive costs of time-consuming coupon experiments by correlating accelerated pitting corrosion in short periods of time with actual pitting corrosion observed over the long term. KW - Pitting corrosion KW - Corrosion acceleration KW - Potentiodynamic tests KW - Phase-field KW - S355 PY - 2025 DO - https://doi.org/10.1016/j.engfailanal.2025.110352 SN - 1350-6307 VL - 184 SP - 1 EP - 20 PB - Elsevier CY - Oxford AN - OPUS4-64805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schaupp, Thomas A1 - Schröder, Nina A1 - Schröpfer, Dirk A1 - Kannengießer, Thomas T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steel - A new look into this issue at narrow groove N2 - Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated. As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding. KW - High-strength structural steel KW - Gas metal arc welding KW - Diffusible hydrogen KW - Hydrogen-assisted cracking KW - TEKKEN KW - Residual stresses KW - Weld metal cracking PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527260 DO - https://doi.org/10.3390/met11060904 VL - 11 IS - 6 SP - 1 EP - 18 PB - MDPI CY - Basel AN - OPUS4-52726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Simon A1 - Hofmann-Böllinghaus, Anja A1 - Chen, Zhimin A1 - Vogel, Kristin A1 - Benner, Philipp T1 - A high-resolution spatiotemporal wildfire propagation dataset for the Mediterranean and Europe N2 - Wildfires are becoming more frequent and severe under the influence of climate change, posing increasing risks to ecosystems, human health, and infrastructure. Accurate spatiotemporal data on wildfire propagation is essential for advancing fire behavior modeling, improving management strategies, and mitigating future impacts. However, existing datasets with both high spatial and temporal resolution are rare, costly, and time-consuming to produce. To address this gap, we present FireSpread_MedEU, a dataset comprising 320 consecutive burned area maps from 103 wildfire events across the Mediterranean and Europe between 2017 and 2023. Burned areas were derived from high-resolution Planet optical satellite imagery (~3 m spatial, mostly daily temporal resolution) using a semi-automated workflow, followed by manual refinement to ensure highest accuracy. Each dataset entry is enriched with detailed metadata and a subjective quality assessment. With its high level of spatiotemporal precision, FireSpread_MedEU provides essential data for the development and validation of machine learning models or wildfire simulation models. It opens new research opportunities in wildfire behavior analysis, risk assessment, and predictive modeling. KW - Wildfire KW - Remote Sensing KW - Data PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657294 DO - https://doi.org/10.1038/s41597-026-06965-2 SN - 2052-4463 VL - 13 IS - 1 SP - 1 EP - 7 PB - Springer Science and Business Media LLC AN - OPUS4-65729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Devi, Sarita A1 - Goel, S. A1 - Rani, S. A1 - Schneider, Rudolf J. A1 - Rohilla, R. A1 - Kumari, Surbhi A1 - Prabhakar, N. T1 - MOF-metal nanohybrid-assisted charge transfer amplification for electrochemical biosensing of the MUC1 cancer biomarker N2 - Cancer is a severe disease characterized by high mortality and complex pathophysiology; however, its early and accurate diagnosis remains inadequate. Conventional diagnostic approaches often fall short, particularly for dense tissues, and are frequently invasive, costly, and of limited availability. This reinforces the need for a compact, economical, and ultrasensitive assay that is operationally simple and interpretable. We present an efficient electrochemical detection platform for the cancer biomarker mucin 1 (MUC1). A fluorine-doped tin oxide (FTO) surface was modified with an iron-based metal–organic framework (FeMOF) intercalated with palladium nanorods (PdNR). FeMOF was prepared using Fe3+/Fe2+ precursors at a 1.2/1 mmol ratio and dual ligands, i.e. tetrahydroxy-1,4-benzoquinone and 2-aminobenzene-1,4-dicarboxylic acid. AntiMUC1 antibodies were immobilized on a modified electrode via p-phenylenediamine (PDA) (FTO/FeMOF@PdNR/PDA/antiMUC1Ab) and evaluated using electrochemical impedance spectroscopy (EIS) and voltammetry. The designed sensor demonstrated an excellent binding affinity for the MUC1 antigen. Among these techniques, the EIS method stands out for its technical performance, as evidenced by the high sensitivity (detection limit 0.074 fg mL−1), quantification limit 0.24 fg mL−1, and high analytical sensitivity (1.39 × 103 Ω fg−1 mL−1 cm−2). The negligible cross-reactivity with interferent biomolecules, rapid response (10-minute equilibrium), regenerability up to 5 cycles, high reproducibility (RSD ∼1–3%), and long-term stability (up to 35 days) further validate the suitability of the proposed MUC1 immunosensor. This study presents an ultrasensitive biosensor that is compact, cost-effective, and easy for individuals at home to use after further development into a kit-based end product. Moreover, its excellent functionality for spiked serum samples shows promise for next-generation clinical diagnostics. KW - Antibodies KW - Metal-organic framework KW - Immunoassay PY - 2026 DO - https://doi.org/10.1039/D6AN00018E SP - 1 EP - 11 PB - Royal Society of Chemistry CY - London AN - OPUS4-65726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sötebier, Carina A1 - Bierkandt, Frank A1 - Rades, Steffi A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Sample loss in asymmetric flow field-flow fractionation coupled to inductively coupled plasma-mass spectrometry of silver nanoparticles N2 - In this work, sample losses of silver nanoparticles (Ag NPs) in asymmetrical flow field-flow fractionation (AF4) have been systematically investigated with the main focus on instrumental conditions like focusing and cross-flow parameters as well as sample concentration and buffer composition. Special attention was drawn to the AF4 membrane. For monitoring possible silver depositions on the membrane, imaging laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) was used. Our results show that the sample residue on the membrane was below 0.6% of the total injected amount and therefore could be almost completely avoided at low sample concentrations and optimized conditions. By investigation of the AF4 flows using inductively coupled plasma mass spectrometry (ICP-MS), we found the recovery rate in the detector flow under optimized conditions to be nearly 90%, while the cross-flow, slot-outlet flow and purge flow showed negligible amounts of under 0.5%. The analysis of an aqueous ionic Ag standard solution resulted in recovery rates of over 6% and the ionic Ag content in the sample was found to be nearly 8%. Therefore, we were able to indicate the ionic Ag content as the most important source of sample loss in this study. KW - Asymmetric flow filed-flow fractionation KW - ICP-MS KW - Nanoparticles KW - Sample loss KW - Quantification PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336171 DO - https://doi.org/10.1039/c5ja00297d SN - 0267-9477 SN - 1364-5544 VL - 30 IS - 10 SP - 2214 EP - 2222 PB - Royal Society of Chemistry CY - London AN - OPUS4-33617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans A1 - Weidner, Steffen A1 - Scheliga, Felix T1 - Ring-Expansion Polymerization (REP) of L-lactide with cyclic Tin(II) Bisphenoxides N2 - Five new cyclic catalysts were prepared by a new synthetic method from tin(II)-2-ethyhexanoate and silylated catechols, silylated 2,2´dihydroxybiphenyl or silylated 1,1´-bisnaphthol. These catalysts were compared with regard to their usefulness as catalysts for the ring expansion polymerization (REP) of L-lactide in bulk at 160 °C, and with two different tin(IV) derivatives of 1,1´binaphthol. Best results were obtained using seven-membered cyclic tin(II)bisphenoxides, which yielded colorless cyclic poly(l-lactide)s free of racemization with weight average molecular weights (Mw) up to 305 000 g mol-1. Furthermore, these catalysts were active even at a lactide/catalyst ratio of 20 000/1. Our new results were superior to those obtained from all other previously published catalysts yielding cyclic poly(L-lactide). The seven-membered cycles also proved to be more active than tin(II) 2-ethylhexanoate with and without the addition of alcohol. KW - Lactide KW - Cyclization KW - Ring-expansion polymerization KW - Tin(II)octanoate KW - MALDI-TOF MS PY - 2019 DO - https://doi.org/10.1016/j.eurpolymj.2019.04.024 SN - 0014-3057 SN - 1873-1945 VL - 116 SP - 256 EP - 264 PB - Elsevier Ltd. AN - OPUS4-47794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Meyer, A. A1 - Weidner, Steffen T1 - High Tm Poly(l-lactide)s by Means of Bismuth Catalysts? N2 - One series of BiSub-catalyzed ring-opening polymerizations (ROPs) is per-formed at 160 °C for 3 days with addition of difunctional cocatalysts to find out, if poly(l-lactide) crystallizes directly from the reaction mixture. An analogous series is performed with monofunctional cocatalysts. High Tm crystal-lites (Tm > 190 °C) are obtained from all bifunctional cocatalysts, but not from all monofunctional ones. It is shown by means of SAXS measurements that the high Tm values are mainly a consequence of a transesterification–homogenization process across the lamellar surfaces resulting in thickness and smoothing of the surfaces. An unusual enthalpy-driven modification of the molecular weight distribution is found for samples that have crystallized during the polymerization. A third series of ROPs is performed at 170 °C for 2 h followed by annealing at 120 °C (2 h) to induce crystallization. Complete transformation of the resulting low Tm crystallites (Tm < 180 °C) into the high Tm crystallites by annealing at 170 °C for 1 d is not achieved, despite variation of the cocatalyst. KW - Polylactide KW - MALDI-TOF MS KW - Crystallization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522777 DO - https://doi.org/10.1002/macp.202100019 SN - 1022-1352 VL - 222 IS - 8 SP - 19 PB - Wiley AN - OPUS4-52277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Meyer, A. T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts(2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and 2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL) are performed at 140 °C in bulk. Small amounts (4 vol%) of chlorobenzene or other solvents are added to facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hmmax, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data. KW - Polylactide KW - MALDI-TOF MS KW - Ring-expansion polymerization KW - Crystals PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565038 DO - https://doi.org/10.1002/macp.202200385 SN - 1022-1352 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-56503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kricheldorf, H. R. T1 - SnOct2-catalyzed ROPs of L-lactide initiated by acidic OH- compounds: Switching from ROP to polycondensation and cyclization N2 - Ring-opening polymerizations (ROPs) of L-lactide are performed in bulk at 130°C with tin(II) 2-ethylhexanoate as catalyst and various phenols of differentacidity as initiators. Crystalline polylactides having phenyl ester end groups are isolated, which are almost free of cyclics. The dispersities and molecular weights are higher than those obtained from alcohol-initiated ROPs under identical conditions. Polymerizations at 160°C yield higher molecular weights than expected from the monomer/initiator ratio and a considerable fraction of cycles. The fraction of cycles increases with higher reactivity of the ester end group indicating that the cycles are formed by end-to-end cyclization. KW - Polylactide KW - MALDI-TOF MS KW - Polymerization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540250 DO - https://doi.org/10.1002/pol.20210823 SN - 2642-4150 VL - 60 IS - 5 SP - 785 EP - 793 PB - Wiley AN - OPUS4-54025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Werthmann, Barbara A1 - Schröder, Hartmut A1 - Just, Ulrich A1 - Borowski, Renate A1 - Decker, Renate A1 - Schwarz, Bärbel A1 - Schmücking, I. A1 - Seifert, Ingetraut T1 - A new approach of characterizing the hydrolytic degradation of poly(ethylene terephthalate) by MALDI-MS N2 - The hydrolytic degradation of technical poly(ethylene terephthalate) (PET) was investigated by means of different methods such as size-exclusion chromatography (SEC), viscometry, light-scattering, thin-layer chromatography, end-group titration, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The long-term degradation was simulated by exposing PET filament yarns to aqueous neutral conditions at 90°C for up to 18 weeks. By means of MALDI-MS and thin-layer chromatography, the formation of different oligomers was obtained during polymer degradation. As expected, an ester scission process was found generating acid terminated oligomers (H-[GT]m-OH) and T-[GT]m-OH and ethylene glycol terminated oligomers (H-[GT]m-G), where G is an ethylene glycol unit and T is a terephthalic acid unit. Additionally, the scission of the ester bonds during the chemical treatment led to a strong decrease in the number of cyclic oligomers ([GT]m). The occurrence of di-acid terminated species demonstrated a high degree of degradation. PY - 1997 DO - https://doi.org/10.1002/(SICI)1099-0518(199708)35:11<2183::AID-POLA9>3.0.CO;2-Z SN - 0360-6376 SN - 0887-624X VL - 35 IS - 11 SP - 2183 EP - 2192 PB - Wiley CY - Hoboken, NJ AN - OPUS4-11357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Musl, O. A1 - Sulaeva, I. A1 - Sumerskii, I. A1 - Mahler, A.K. A1 - Rosenau, T. A1 - Falkenhagen, Jana A1 - Potthast, A. T1 - Mapping of the Hydrophobic Composition of Lignosulfonates N2 - Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in molar mass (molar mass distribution-MMD) and in functionalities (functionality-type distribution - FTD), which crucially affect their material usage. In terms of FTD, state-of-the-art Lignin analytics still rely mainly on the determination of functional group contents, which are statistical averages with limited explanatory power. In contrast, our online hydrophobic interaction chromatography−size-exclusion chromatography 2D-LC approach combines the determination of both MMD and FTD in a single measurement to provide a comprehensive picture of the characteristic composition of industrial lignosulfonates information hitherto inaccessible by state-of-the-art lignin analytics. In this way, the complex inter - relationships between these two important structural parameters can be studied in an unprecedented manner. In this study, we reveal the considerable differences in terms of hydrophobic composition and its dispersity present in a range of different industrial lignosulfonates - data desperately needed in tailoring and refining of lignosulfonate composition for material usage. KW - Lignosulfonates KW - Amphiphilicity KW - Hydrophobic interaction chromatography KW - Two-dimensional chromatography (2D-LC) KW - Charge-to-size-ratio PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538612 DO - https://doi.org/10.1021/acssuschemeng.1c06469 VL - 9 IS - 49 SP - 16786 EP - 16795 PB - ASC Publications AN - OPUS4-53861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Reversible Polycondensations outside the Jacobson-Stockmayer Theory and a New Concept of Reversible Polycondensations N2 - L-Lactide was polymerized with tin(II)acetate, tin(II)2-ethyl hexanoate, diphenyltin dichloride and dibutyltin bis(pentafluorophenoxide) at 130 °C in bulk. When an alcohol was added as initiator, linear chains free of cycles were formed having a degree of polymerization (DP) according to the lactide/initiator (LA/In) ratio. Analogous polymerizations in the absence of an initiator yielded high molar mass cyclic polylactides. Quite similar results were obtained when ε-caprolactone was polymerized with or without initiator. Several transesterification experiments were conducted at 130 °C, either with polylactide or poly(ε-caprolactone) indicating that several transesterification mechanisms are operating under conditions that do not include formation of cycles by back-biting. Furthermore, reversible polycondensations (revPOCs) with low or moderate conversions were found that did not involve any kind of cyclization. Therefore, These results demonstrate the existence of revPOCs, which do neither obey the theory of irreversible polycondensation as defined by Flory nor the hypothesis of revPOCs as defined by Jacobson and Stockmayer. A new concept encompassing any kind of revPOCs is formulated in the form of a “polycondensation triangle”. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530831 DO - https://doi.org/10.1039/d1py00704a VL - 12 IS - 35 SP - 5003 EP - 5016 PB - Royal Society for Chemistry AN - OPUS4-53083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Meyer, A. T1 - High Tm linear poly(L-lactide)s prepared via alcohol-initiated ROPs of L-lactide N2 - Alcohol-initiated ROPs of L-lactide were performed in bulk at 160 °C for 72 h with variation of the catalyst or with variation of the initiator (aliphatic alcohols). Spontaneous crystallization was only observed when cyclic Sn(II) compounds were used as a catalyst. Regardless of initiator, high melting crystallites with melting temperatures (Tm) of 189–193 °C were obtained in almost all experiments with Sn(II) 2,2′-dioxybiphenyl (SnBiph) as catalyst, even when the time was shortened to 24 h. These HTm poly(lactide)s represent the thermodynamically most stable form of poly(L-lactide). Regardless of the reaction conditions, such high melting crystallites were never obtained when Sn(II) 2-ethylhexanoate (SnOct2) was used as catalyst. SAXS measurements evidenced that formation of HTm poly(L-lactide) involves growth of the crystallite thickness, but chemical modification of the crystallite surface (smoothing) seems to be of greater importance. A hypothesis, why the “surface smoothing” is more effective for crystallites of linear chains than for crystallites composed of cycles is discussed. KW - Polylactide KW - MALDI-TOF MS KW - Ring-opening polymerization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524330 DO - https://doi.org/10.1039/d1ra01990b VL - 11 IS - 23 SP - 14093 EP - 14102 PB - Royal Society of Chemistry AN - OPUS4-52433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Scheliga, F. A1 - Weidner, Steffen T1 - What does conversion mean in polymer science? N2 - The definition of the term “conversion” is discussed for a variety of polymer syntheses. It is demonstrated that in contrast to organic and inorganic chemistry several different definitions are needed in polymer science. The influence of increasing conversion on structure and topology of homo- and Copolymers is illustrated. Chain-growth polymerizations, such as radical polymerization or living anionic polymerizations of vinyl monomers, condensative chain polymerization, two and three-dimensional step-growth polymerizations, ring–ring or chain–chain equilibration and chemical modification of polymers are considered. KW - Polymers KW - Polymerization KW - Conversion KW - Polycondensation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523597 DO - https://doi.org/10.1002/macp.202100010 VL - 222 IS - 8 SP - 10 PB - Wiley VCH AN - OPUS4-52359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - The role of transesterifications in reversible polycondensations and a reinvestigation of the Jacobson-Beckmann-Stockmayer experiments N2 - The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations. These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543402 DO - https://doi.org/10.1039/d1py01679b SN - 1759-9962 SP - 1 EP - 9 PB - RSC Publ. CY - Cambridge AN - OPUS4-54340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Scheliga, F. T1 - Ring-Expansion Polymerization of 𝝐-Caprolactone, Glycolide, and l-lactide with a Spirocyclic Tin(IV) Catalyst Derived from or 2,2′-Dihydroxy-1,1′-Binaphthyl – New Results and a Revision N2 - In contrast to other cyclic tin bisphenoxides, polymerizations of glycolide and l-lactide with the spirocyclic tin(IV) bis-1,1′-bisnapthoxide yield linear chains having a 1,1′-bisnapthol end group and no cycles. In the case of l-lactide, LA/Cat ratio and temperature are varied and at 160 °C or below, all polylactides mainly consist of even-numbered chains. A total predominance of even-numbered chains is also found for homopolymerization of glycolide, or the copolymerization of glycolide and l-lactide, when conducted <120 °C. Linear chains having a bisnaphthol end group are again the main reaction products of ring-expansion polymerizations (REP) of 𝝐-caprolactone, but above 150 °C cycles are also formed. KW - Polylactide KW - MALDI-TOF MS KW - Polymerization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541931 DO - https://doi.org/10.1002/macp.202100308 VL - 222 IS - 24 SP - 1 EP - 10 PB - Wiley VCH GmbH AN - OPUS4-54193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chandna, Sanjam A1 - Povolotsky, Tatyana L. A1 - Nie, Chuanxiong A1 - Schwartz, Sophia A1 - Wedepohl, Stefanie A1 - Quaas, Elisa A1 - Ludwig, Kai A1 - Boyakova, Yulia A1 - Bhatia, Sumati A1 - Meyer, Klas A1 - Falkenhagen, Jana A1 - Haag, Rainer A1 - Block, Stephan T1 - Lignin-Based Mucus-Mimicking Antiviral Hydrogels with Enzyme Stability and Tunable Porosity N2 - Mucus is a complex hydrogel that acts as a defensive and protective barrier in various parts of the human body. Therise in the level of viral infections has underscored the importance of advancing research into mucus-mimicking hydrogels for theefficient design of antiviral agents. Herein, we demonstrate the gram-scale synthesis of biocompatible, lignin-based virus-bindinginhibitors that reduce waste and ensure long-term availability. The lignin-based inhibitors are equipped with sulfate moieties, whichare known binding partners for many viruses, including SARS-CoV-2 and herpes viruses. In addition, cross-linking the synthesizedinhibitors yielded hydrogels that mimicked native mucus concerning surface functionality and rheology. The degree of sulfationexhibits a very strong impact on the mesh size distribution of the hydrogels, which provides a new means to fine-tune the steric andelectrostatic contributions of the virus−hydrogel interaction. This feature strongly impacts the sequestration capability of the lignin-based hydrogels, which is demonstrated by infection inhibition assays involving human herpes simplex virus 1, influenza A viruses,and the bacterium Escherichia coli (E. coli). These measurements showed a reduction in plaque-forming units (HSV-1) and colony-forming units (E. coli) by more than 4 orders of magnitude, indicating the potent inhibition by the lignin-based hydrogels KW - Lignin functionalization KW - Mucus-mimicking hydrogels PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625301 DO - https://doi.org/10.1021/acsami.4c18519 SP - 1 EP - 14 PB - American Chemical Society (ACS) CY - USA AN - OPUS4-62530 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen T1 - H2O-Initiated Polymerization of L-Lactide N2 - Water-initiated ring-opening polymerizations (ROPs) of L-lactide (LA) were performed in bulk at 140 °C, whereupon 11 different salts or complexes of low-toxic metal ions such as tin (II), Zn(II), Zr(IV), and Bi(III) were used as catalysts. Only four catalysts gave satisfactory results despite a long reaction time (24 h). The influence of the temperature was studied with tin (II) 2-ethylhexanoate (SnOct2), dibutyltin oxide (Bu2SnO), and zinc bis-acetylacetonate (Zn(acac)2) and zirconium acetylacetonate (Zr(acac)4). With SnOct2, Bu2SnO and Zr(acac)4 the time was varied at 140 °C to compare their reactivity. Furthermore, two series of ROPs were carried out with variation of the LA/H2O ratio to verify the control of the molecular weight by the monomer-initiator ratio. Bi- or tri-modal molecular weight distributions (MWD) were found for most of the ROPs and bimodal melting endotherms in the differential scanning calorimetry (DSC) heating traces. The thickness and dependence of the 3D packing of the crystallites were monitored by small-angle X-ray scattering (SAXS) measurements. KW - MALDI-TOF MS KW - Polylactide KW - Ring-opening polymerization KW - Crystallization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628761 DO - https://doi.org/10.1007/s10924-025-03565-w SN - 1572-8919 VL - 33 IS - 6 SP - 2843 EP - 2857 PB - Springer Science and Business Media LLC CY - New York, NY AN - OPUS4-62876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Scheliga, Felix A1 - Kricheldorf, Hans R. T1 - Polycondensation, Cyclization and Disproportionation of Solid Poly(L-lactide) Trifluoroethyl Esters and the Simultaneous Formation of Extended Chain Crystals and Extended Ring Crystals N2 - Two poly(L-lactide)s (PLAs) with a degree of polymerization (DP) of 20 or 100 were prepared by trifluoroethanol-initiated ring-opening polymerization (ROP) catalyzed by tin(II) 2-ethyl hexanoate (SnOct2). These PLAs were annealed at 140 ◦C or at 160 ◦C in the presence of SnOct2, and the changes in topology and molecular weight distribution (MWD) were monitored by matrix-assisted laser desorption/ionization time-of flight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC). For the PLA with a DP 20, the main reaction was polycondensation combined with higher dispersities. In the case of the DP 100, PLA polycondensation was combined with disproportionation and the formation of a new MWD maximum around m/z 3500. In addition, extensive cyclization occurred, and the resulting cyclic PLAs crystallized separately from the linear chains in the form of extended ring crystals. These results also suggest that both extended chain and extended ring crystals posses the same crystal thickness as a result of thermodynamically controlled transesterification in the solid state. KW - Polycondensation KW - MALDI KW - Polylactide KW - Cyclization PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616441 DO - https://doi.org/10.1016/j.polymer.2024.127800 VL - 315 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-61644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Dalgic, Mete-Sungur A1 - Weidner, Steffen T1 - Quantitative MALDI-TOF Mass Spectrometry of Star-Shaped Polylactides Based on Chromatographic Hyphenation N2 - The end groups of three- and four-arm star-shaped polylactides (PLA) with trimethylolpropane and pentaerythritol core structures were functionalized with acetic acid. Reaction products with different degrees of functionalization were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Additional gradient elution liquid adsorption chromatography (GELAC) measurements were performed to determine the degree of functionalization. This technique enabled clear separation and sufficient quantification of the formed species. These chromatographic data could be used inversely to quantify mass spectrometric results, which are usually biased by the unknown ionization probabilities of different polymer end group structures. Our results showed that, in this particular case, the peak intensity in the MALDITOF mass spectra can be used to semiquantitatively determine the degree of functionalization in incompletely functionalized multiarm PLA. KW - Polylactides KW - MALDI-TOF-MS KW - Gradient elution liquid adsorption chromatography PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625292 DO - https://doi.org/10.1021/jasms.4c00491 SN - 1879-1123 SP - 1 EP - 9 PB - American Chemical Society (ACS) AN - OPUS4-62529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen A1 - Scheliga, Felix T1 - Polycondensation of L-lactic acid: a deeper look into solid state polycondensation N2 - L-Lactic acid (LA) was condensed in the presence of SnCl2 or 4-toluenesulfonic acid (TSA) at 140 °C, and chain growth without cyclization was observed. In addition, poly(L-lactic acid)s (PLAs) with a degree of polymerization (DP) of 25, 50 or 100 were prepared by water-initiated ring-opening polymerization (ROP). These PLAs were annealed in the solid state at 140 °C and 160 °C in the presence of tin(II) 2-ethylhexanoate (SnOct2, SnCl2 or TSA). The changes in the molar mass distribution and in the topology were characterized by means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and size exclusion chromatography (SEC). With increasing time, fewer side reactions caused higher molar masses and increasing fractions of cyclic polylactides (cPLA) were obtained. Their “saw tooth” pattern in the MALDI-TOF mass spectra indicated the formation of extended ring crystallites in the solid state. TSA was the most active catalyst and caused fewer side reactions than SnCl2, which was the least reactive catalyst. Acetylation of the CH-OH end groups hindered polycondensation and prevented the formation of cPLAs. Reaction mechanisms will be discussed. KW - MALDI-TOF MS KW - Polycondensation KW - Polylaktide KW - Solid state PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625271 DO - https://doi.org/10.1039/d4py01191k SN - 1759-9962 SP - 1 EP - 9 PB - Royal Society of Chemistry (RSC) AN - OPUS4-62527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Jan A1 - Dudziak, Mateusz A1 - Falkenhagen, Jana A1 - Rockel, Daniel A1 - Reimann, H.-A A1 - Schartel, Bernhard T1 - This is the way: An evidence based route to phytic-acid–based flame retardant poly(lactide acid) N2 - A systematic sequence of materials was investigated to develop phytic-acid (Phyt)–based flame retarded poly (lactide acid) (PLA), while factoring in molecular weight (MW), crystallinity and mechanical properties. Synergistic approaches were developed based on combinations with lignin and expandable graphite (EG), as well as by applying different Phyt salts of melamine (Mel), piperazine (Pip), and arginine (Arg). Compounds were twin screw extruded, injection molded, hot pressed and investigated with thermal analysis, size exclusion chromatography, infrared spectroscopy, tensile testing, limited oxygen index (LOI), UL 94, cone calorimeter, and scanning electron microscope. 16.7 wt.% flame retardant (FR) slightly enhances crystallization while MW remains unchanged in PLA Phyt Arg and PLA Phyt Mel. LOI was improved to 43.7 vol.% for PLA Phyt Arg, UL 94 V0 achieved for PLA Phyt Pip. Cone calorimeter results show total heat evolved reduced by 14 %, maximum average rate of heat emission 43 % lower, and peak heat release rate reduced by 50 % for PLA Phyt Mel. Phyt Mel combined with EG increased the char yield of PLA to 20 wt.% and 15.5 wt.% at 600 and 900 ◦C, respectively. Phyt is exploited to enhance char yield, stabilize the intumescent char, and lower the apparent effective heat of combustion. The combination of Phyt Mel and EG was proposed as an efficient FR for PLA via an evidence based developing route. KW - Polylactide acid KW - Intumescent flame retardant KW - Phosphorous flame retardant KW - Phytic acid KW - Expandable graphite KW - Melamine PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626395 DO - https://doi.org/10.1016/j.polymdegradstab.2025.111242 SN - 1873-2321 SN - 0141-3910 VL - 234 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-62639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -