TY - JOUR A1 - Wang, S. A1 - Cai, Y. A1 - Guo, H. A1 - Wu, Dejian A1 - Xie, Y. T1 - Effect of fuel concentration, inert gas dilutions, inert gas–water mist twin fluid medium dilutions, and end boundary condition on overpressure transients of premixed fuel vapor explosion N2 - A series of experiments were conducted in a 10L closed and vented tube with L/D = 10.0, and effects of initial fuel volume concentration, inert gas dilutions (diluted by N2 and CO2), inert gas–water mist twin fluid medium dilutions (diluted by N2-H2O twin fluid medium, CO2-H2O twin fluid medium) and end boundary conditions on overpressure transients of hydrocarbon fuel–air mixtures explosion were revealed. Results show that the overpressure-time profiles consistent with the dynamic evolution law of ‘approximately zero-1st overpressure rising stage-2nd overpressure rising stage-descending stage’, and ‘rate of overpressure rise-time’ curves exhibit the characteristics of multi-stages and multi-peaks, such as (dp/dt)(1,max), (dp/dt)(1,min), (dp/dt)(2,max) and (dp/dt)(2,min). Specifically, as the fuel volume concentration increased, both the maximum overpressures (pmax), and the maximum rates of overpressure rise ((dp/dt)(1,max) and (dp/dt)(2,max)) show a variation trend of increasing firstly and then decreasing, while the corresponding times (tmax, θ(1,max) , θ(2,max)) show a total different variation trend. Moreover, when YCH is lower than 1.88%, the value of (dp/dt)(1,max) is greater than (dp/dt)(2,max), while the value of (dp/dt)(1,max) was less than (dp/dt)(2,max), and when YCH was higher than 1.88%. The addition of N2 and CO2 can obviously inhibit the explosion intensity of hydrocarbon fuel, and the inhibition effect of CO2 is better than that of N2. Due to the synergy inhibition effect of the inert gas and ultrafine water mist, all the values of pmax, (dp/dt)(1,max) and (dp/dt)(2,max) diluted by inert gas-ultrafine water mist twin fluid medium were smaller than those diluted by sole inert gases. In addition, there are significant differences in the overpressure-time and the rate of overpressure rise-time profiles between closed and end venting explosions. The values of maximum overpressure and the rates of overpressure rise of the closed explosion were higher than those of the venting explosion, but the minimum rate of overpressure rise is a smaller one. KW - Premixed fuel vapour KW - Overpressure transients KW - Inert gas KW - Diluent additions KW - Twin fluid medium KW - Venting boundary condition PY - 2021 DO - https://doi.org/10.1016/j.fuel.2021.122083 SN - 0016-2361 VL - 309 SP - 1 EP - 16 PB - Elsevier Ltd. AN - OPUS4-55055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hellemans, S. A1 - Rocha, M. M. A1 - Wang, M. A1 - Romero Arias, J. A1 - Aanen, D. K. A1 - Bagnères, A.-G. A1 - Buček, A. A1 - Carrijo, T. F. A1 - Chouvenc, T. A1 - Cuezzo, C. A1 - Constantini, J. P. A1 - Constantino, R. A1 - Dedeine, F. A1 - Deligne, J. A1 - Eggleton, P. A1 - Evans, T. A. A1 - Hanus, R. A1 - Harrison, Mark C. A1 - Harry, M. A1 - Josens, G. A1 - Jouault, C. A1 - Kalleshwaraswamy, C. M. A1 - Kaymak, E. A1 - Korb, J. A1 - Lee, C.-Y. A1 - Legendre, F. A1 - Li, H.-F. A1 - Lo, N. A1 - Lu, T. A1 - Matsuura, K. A1 - Maekawa, K. A1 - McMahon, Dino Peter A1 - Mizumoto, N. A1 - Oliveira, D. E. A1 - Poulsen, M. A1 - Sillam-Dussès, D. A1 - Su, N.-Y. A1 - Tokuda, G. A1 - Vargo, E. L. A1 - Ware, J. L. A1 - Šobotník, J. A1 - Scheffrahn, R. H. A1 - Cancello, E. A1 - Roisin, Y. A1 - Engel, M. S. A1 - Bourguignon, T. T1 - Genomic data provide insights into the classification of extant termites N2 - The higher classification of termites requires substantial revision as the Neoisoptera, the most diverse termite lineage, comprise many paraphyletic and polyphyletic higher taxa. Here, we produce an updated termite classification using genomic-scale analyses. We reconstruct phylogenies under diverse substitution models with ultraconserved elements analyzed as concatenated matrices or within the multi-species coalescence framework. Our classification is further supported by analyses controlling for rogue loci and taxa, and topological tests. We show that the Neoisoptera are composed of seven family-level monophyletic lineages, including the Heterotermitidae Froggatt, Psammotermitidae Holmgren, and Termitogetonidae Holmgren, raised from subfamilial rank. The species-rich Termitidae are composed of 18 subfamily-level monophyletic lineages, including the new subfamilies Crepititermitinae, Cylindrotermitinae, Forficulitermitinae, Neocapritermitinae, Protohamitermitinae, and Promirotermitinae; and the revived Amitermitinae Kemner, Microcerotermitinae Holmgren, and Mirocapritermitinae Kemner. Building an updated taxonomic classification on the foundation of unambiguously supported monophyletic lineages makes it highly resilient to potential destabilization caused by the future availability of novel phylogenetic markers and methods. The taxonomic stability is further guaranteed by the modularity of the new termite classification, designed to accommodate as-yet undescribed species with uncertain affinities to the herein delimited monophyletic lineages in the form of new families or subfamilies. KW - Termite KW - Taxonomy KW - Evolution PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608276 DO - https://doi.org/10.1038/s41467-024-51028-y VL - 15 IS - 1 SP - 1 EP - 17 PB - Springer Science and Business Media LLC AN - OPUS4-60827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, Q. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed A. A1 - Yang, Z. A1 - Wang, S. A1 - Gao, Y. A1 - Shang, J. A1 - Hunger, J. A1 - Aldiyarov, A. A1 - Schönhals, Andreas A1 - Ge, Y. A1 - Qi, Z. T1 - Molecular engineering of supramolecular polymer adhesive with confined water and a single crown ether N2 - Here, we report a water-induced supramolecular polymer built from confined structural water and an intrinsic amphiphilic macrocyclic self-assembly in a nanophase separated structure. The newly designed crown ether macrocycle, featuring strong hydrophilic hydrogen bonding receptor selenoxide and a synergistical hydrophobic selenium-substituted crown core, confines the structural water in a segregated, interdigitated architecture. Although water molecules typically freeze around 0 °C, the confined structural water in this supramolecular polymer remains in a liquid-like state down to 80 °C. Previous studies suggest that multiple crown ether units are needed to generate structural water. However, here, one unit is sufficient to control the formation and disappearance of structural water and consequent supramolecular polymerization. Typically, the DC conductivity of water shows Arrhenius temperature dependency (lnσDC ∝ 1/T). In contrast, this new crown unit maintains water in confined states, which exhibit a Vogel/Fulcher/Tammann behavior (lnσDC ∝ 1/(T-T0)) at temperatures above the glass transition temperature. Moreover, this water-induced supramolecular polymer exhibits remarkable adhesion properties to hydrophilic surfaces and maintains tough adhesion at low temperatures. These findings show how a single small macrocycle can govern the complex structure and functionality of water in supramolecular systems. KW - Supramolecular polymerization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623631 DO - https://doi.org/10.1039/D4SC06771A SN - 2041-6539 VL - 16 SP - 1 EP - 9 PB - RSC AN - OPUS4-62363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Song, X. A1 - Ma, Y. A1 - Wang, C. A1 - Dietrich, Paul A1 - Unger, Wolfgang A1 - Luo, Y. T1 - Effects of protonation, hydrogen bonding, and photodamaging on X-ray spectroscopy of the amine terminal group in aminothiolate monolayers N2 - The amine headgroup, NH2, in aminothiolate monolayers can often generate unexpectedly rich structures in its N K-edge X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectra that are difficult to assign. We have carried out density functional theory (DFT) calculations to study the XPS and NEXAFS of amine headgroup in four different aminothiolate monolayers, namely, aliphatic 11-aminoundecane-1-thiol (AUDT), aromatic 4-aminobenzenethiol (ABT), araliphatic 4-aminophenylbutane-1-thiol (APBT), and 3-(4''-amino-1,1':4',1''-terphenyl-4-yl)propane-1-thiol (ATPT), with the focus on structure changes caused by protonation, hydrogen bonding, and X-ray damaging. Spectra of all possible saturated and unsaturated species, as well as X-ray damage products, such as imine, nitrile, azo species, and cumulative double bonds, have been thoroughly examined. It is found that extra spectral structures observed in the experimental XPS spectra do not result from protonation but from the formation of a primary ammonium. The X-ray excitation can induce cross-linking between two neighboring molecules to form different complexes that contribute to the π* features in NEXAFS spectra. KW - Surface analysis KW - Spectrum simulation KW - X-ray absorption spectroscopy KW - Self assembling monolayer PY - 2012 DO - https://doi.org/10.1021/jp302716w SN - 1932-7447 SN - 1089-5639 VL - 116 IS - 23 SP - 12649 EP - 12654 PB - Soc. CY - Washington, DC AN - OPUS4-26255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Z. A1 - Villa Santos, C. A1 - Legrand, A. A1 - Haase, F. A1 - Hara, Y. A1 - Kanamori, K. A1 - Aoyama, T. A1 - Urayama, K. A1 - Doherty, C. M. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Colon, Y. J. A1 - Furukawa, S. T1 - Multiscale structural control of linked metal–organic polyhedra gel by aging-induced linkage-reorganization N2 - Assembly of permanently porous metal–organic polyhedra/cages (MOPs) with bifunctional linkers leads to soft supramolecular networks featuring both porosity and processability. However, the amorphous nature of such soft materials complicates their characterization and thus limits rational structural control. Here we demonstrate that aging is an effective strategy to control the hierarchical network of supramolecular gels, which are assembled from organic ligands as linkers and MOPs as junctions. Normally, the initial gel formation by rapid gelation leads to a kinetically trapped structure with low controllability. Through a controlled post-synthetic aging process, we show that it is possible to tune the network of the linked MOP gel over multiple length scales. This process allows control on the molecular-scale rearrangement of interlinking MOPs, mesoscale fusion of colloidal particles and macroscale densification of the whole colloidal network. In this work we elucidate the relationships between the gel properties, such as porosity and rheology, and their hierarchical structures, which suggest that porosity measurement of the dried gels can be used as a powerful tool to characterize the microscale structural transition of their corresponding gels. This aging strategy can be applied in other supramolecular polymer systems particularly containing kinetically controlled structures and shows an opportunity to engineer the structure and the permanent porosity of amorphous materials for further applications. KW - SAXS KW - Metal-organic polyhedra KW - Structural control PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532309 DO - https://doi.org/10.1039/d1sc02883a SN - 1478-6524 SN - 1742-2183 VL - 12 IS - 38 SP - NIL_1 EP - NIL_9 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-53230 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Q. A1 - Zheng, M. A1 - Huang, Y. A1 - Kunte, Hans-Jörg A1 - Wang, X. A1 - Liu, Y. A1 - Zheng, C. T1 - Long term corrosion estimation of carbon steel, titanium and its alloy in backfill material of compacted bentonite for nuclear waste repository N2 - The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers. The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future Container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 106 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel. KW - Issues KW - Disposal KW - Performance KW - Moisture KW - Lifetime KW - Water KW - Model PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492413 DO - https://doi.org/10.1038/s41598-019-39751-9 SN - 2045-2322 VL - 9 SP - 3195 PB - Nature Publishing Group AN - OPUS4-49241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, Y.-H. A1 - Descalzo López, Ana Belén A1 - Sgen, Z. A1 - Röhr, Holger A1 - Liu, Q. A1 - Wang, Y.-W. A1 - Spieles, Monika A1 - Li, Y.-Z. A1 - Rurack, Knut A1 - You, X.-Z. T1 - Mono- and Di(dimethylamino)styryl-Substituted Borondipyrromethene and Borondiindomethene Dyes with Intense Near-Infrared Fluorescence N2 - Four novel borondipyrromethene (BDP) and -diindomethene (BDI) dyes with one or two (dimethylamino)styryl extensions at the chromophore were synthesized and spectroscopically investigated. An X-ray crystal structure shows that the extended auxochrome is virtually planar. All dyes thus display intense red/near infrared (NIR) absorption and emission. The (dimethylamino)styryl group induces a charge-transfer character that entails bright solvatochromic fluorescence, which is only quenched with increasing solvent polarity according to the energy-gap law. The dye with an additional dimethylanilino group at the meso position of BDP shows a remarkable switching of lipophilicity by protonation. Two dyes with an 8-hydroxyquinoline ligand at the meso position display quenched emission in the presence of Hg2+ or Al3+ owing to electron transfer from the excited BDP to the complexed receptor. The BDI dye presents a pH indicator with bright fluorescence and extremely low fluorescence anisotropy. KW - Borondipyrromethene KW - Dyes KW - Fluorescence KW - Indicators KW - Protonation PY - 2006 DO - https://doi.org/10.1002/asia.200600042 SN - 1861-4728 SN - 1861-471X VL - 1 IS - 1-2 SP - 176 EP - 187 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - He, Shulin A1 - Sieksmeyer, Thorben A1 - Che, Y. A1 - Mora, M. A. E. A1 - Stiblik, P. A1 - Banasiak, Ronald A1 - Harrison, M. C. A1 - Sobotnik, J. A1 - Wang, Z. A1 - Johnston, P. R. A1 - McMahon, Dino Peter T1 - Evidence for reduced immune gene diversity and activity during the evolution of termites N2 - The evolution of biological complexity is associated with the emergence of bespoke immune systems that maintain and protect organism integrity. Unlike the well-studied immune systems of cells and individuals, little is known about the origins of immunity during the transition to eusociality, a major evolutionary transition comparable to the evolution of multicellular organisms from single-celled ancestors. We aimed to tackle this by characterizing the immune gene repertoire of 18 cockroach and termite species, spanning the spectrum of solitary, subsocial and eusocial lifestyles. We find that key transitions in termite sociality are correlated with immune gene family contractions. In cross-species comparisons of immune gene expression, we find evidence for a caste-specific social defence system in termites, which appears to operate at the expense of individual immune protection. Our study indicates that a major transition in organismal complexity may have entailed a fundamental reshaping of the immune system optimized for group over individual defence. KW - Social insect KW - Subsocial KW - Cockroach KW - Major transition KW - Contraction KW - Expansion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538878 DO - https://doi.org/10.1098/rspb.2020.3168 SN - 0962-8452 SN - 1471-2954 VL - 288 IS - 1945 SP - 1 EP - 10 PB - The Royal Society CY - London AN - OPUS4-53887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huan, Y. A1 - Gojani, Ardian A1 - Gornushkin, Igor B. A1 - Wang, X. A1 - Liu, D. A1 - Rong, M. T1 - Dynamics of laser-induced plasma splitting N2 - The dynamics of laser-induced plasma plume splitting is investigated using spatiotemporal plasma imaging and spectrometry in this paper. Plasma plume splitting into fast and slow components is clearly observed using plasma optical emission as time evolves. The spatial resolved plasma spectra are used to investigate the plasma species distribution, which reveals that the charged copper ions, which radiate at wavelength range 485 nm - 504 nm, are merely present in the fast component. In order to further interpret the mechanism, the pressure-dependent and laser energy-dependent plume splitting are analyzed. Based on the results, the charge separation field is proposed to explain this phenomenon. This work can be of importance for such areas as laser induced breakdown spectroscopy, laser-induced ion source formation, pulse laser deposition, film growth, and nanoscale synthesis. KW - Spectroscopy KW - Laser induced plasma KW - Splitting KW - Imaging PY - 2020 DO - https://doi.org/10.1016/j.optlaseng.2019.105832 SN - 0143-8166 VL - 124 SP - 1 EP - 5 PB - Elsevier CY - Amsterdam AN - OPUS4-48746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prohaska, T. A1 - Irrgeher, J. A1 - Benefield, J. A1 - Böhlke, J. K. A1 - Chesson, L. A. A1 - Coplen, T. B. A1 - Ding, T. A1 - Dunn, P. J. H. A1 - Gröning, M. A1 - Holden, N. E. A1 - Meijer, H. A. J. A1 - Moossen, H. A1 - Possolo, A. A1 - Takahashi, Y. A1 - Vogl, Jochen A1 - Walczyk, T. A1 - Wang, J. A1 - Wieser, M. E. A1 - Yoneda, S. A1 - Zhu, X.-K. A1 - Meija, J. T1 - Standard atomic weights of the elements 2021 (IUPAC Technical Report) N2 - Following the reviews of atomic-weight determinations and other cognate data in 2015, 2017, 2019 and 2021, the IUPAC (International Union of Pure and Applied Chemistry) Commission on Isotopic Abundances and Atomic Weights (CIAAW) reports changes of standard atomic weights. The symbol Ar(E) was selected for standard atomic weight of an element to distinguish it from the atomic weight of an element E in a specific substance P, designated Ar(E, P). The CIAAW has changed the values of the standard atomic weights of five elements based on recent determinations of terrestrial isotopic abundances: Ar (argon): from 39.948 ± 0.001 to [39.792, 39.963] Hf (hafnium): from 178.49 ± 0.02 to 178.486 ± 0.006 Ir (iridium): from 192.217 ± 0.003 to 192.217 ± 0.002 Pb (lead): from 207.2 ± 0.1 to [206.14, 207.94] Yb (ytterbium): from 173.054 ± 0.005 to 173.045 ± 0.010 The standard atomic weight of argon and lead have changed to an interval to reflect that the natural variation in isotopic composition exceeds the measurement uncertainty of Ar(Ar) and Ar(Pb) in a specific substance. The standard atomic weights and/or the uncertainties of fourteen elements have been changed based on the Atomic Mass Evaluations 2016 and 2020 accomplished under the auspices of the International Union of Pure and Applied Physics (IUPAP). Ar of Ho, Tb, Tm and Y were changed in 2017 and again updated in 2021: Al (aluminium), 2017: from 26.981 5385 ± 0.000 0007 to 26.981 5384 ± 0.000 0003 Au (gold), 2017: from 196.966 569 ± 0.000 005 to 196.966 570 ± 0.000 004 Co (cobalt), 2017: from 58.933 194 ± 0.000 004 to 58.933 194 ± 0.000 003 F (fluorine), 2021: from 18.998 403 163 ± 0.000 000 006 to 18.998 403 162 ± 0.000 000 005 (Ho (holmium), 2017: from 164.930 33 ± 0.000 02 to 164.930 328 ± 0.000 007) Ho (holmium), 2021: from 164.930 328 ± 0.000 007 to 164.930 329 ± 0.000 005 Mn (manganese), 2017: from 54.938 044 ± 0.000 003 to 54.938 043 ± 0.000 002 Nb (niobium), 2017: from 92.906 37 ± 0.000 02 to 92.906 37 ± 0.000 01 Pa (protactinium), 2017: from 231.035 88 ± 0.000 02 to 231.035 88 ± 0.000 01 Pr (praseodymium), 2017: from 140.907 66 ± 0.000 02 to 140.907 66 ± 0.000 01 Rh (rhodium), 2017: from 102.905 50 ± 0.000 02 to 102.905 49 ± 0.000 02 Sc (scandium), 2021: from 44.955 908 ± 0.000 005 to 44.955 907 ± 0.000 004 (Tb (terbium), 2017: from 158.925 35 ± 0.000 02 to 158.925 354 ± 0.000 008) Tb (terbium), 2021: from 158.925 354 ± 0.000 008 to 158.925 354 ± 0.000 007 (Tm (thulium), 2017: from 168.934 22 ± 0.000 02 to 168.934 218 ± 0.000 006) Tm (thulium), 2021: from 168.934 218 ± 0.000 006 to 168.934 219 ± 0.000 005 (Y (yttrium), 2017: from 88.905 84 ± 0.000 02 to 88.905 84 ± 0.000 01) Y (yttrium), 2021: from 88.905 84 ± 0.000 01 to 88.905 838 ± 0.000 002 KW - Argon KW - Ciaaw.org KW - Hafnium KW - Iridium KW - Lead KW - LSVEC KW - Ytterbium PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548443 DO - https://doi.org/10.1515/pac-2019-0603 SN - 0033-4545 VL - 94 IS - 5 SP - 573 EP - 600 PB - De Gruyter Verlag CY - Berlin AN - OPUS4-54844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Daireaux, A. A1 - Wielgosz, R. A1 - Davies, S. A1 - Wang, H. A1 - Rodrigues, J. A1 - Wollinger, W. A1 - Windust, A. A1 - Kang, M. A1 - Fuhai, S. A1 - Philipp, Rosemarie A1 - Kuhlich, Paul A1 - Wong, S.-K. A1 - Shimizu, Y. A1 - Pérez, M. A1 - Avila, M. A1 - Fernandes-Whaley, M. A1 - Prevoo, D. A1 - de Vos, J. A1 - Visser, R. A1 - Archer, M. A1 - LeGoff, T. A1 - Wood, S. A1 - Bearden, D. A1 - Bedner, M. A1 - Boroujerdi, A. A1 - Duewer, D. A1 - Hancock, D. A1 - Lang, B. A1 - Porter, B. A1 - Schantz, M. A1 - Sieber, J. A1 - White, E. A1 - Wise, S. A. T1 - Final report on key comparison CCQM-K55.a (estradiol): an international comparison of mass fraction purity assignment of estradiol N2 - Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.a, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2009/2010. Eleven national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of estradiol present as the main component in the comparison sample (CCQM-K55.a) which consisted of a bulk estradiol hemihydrate material obtained from a commercial supplier that had been extensively but not exhaustively dried prior to sub-division into the units supplied for the comparison. Estradiol was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300–500 Da] and low polarity (pKOW < -2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC) or by high performance liquid chromatography (LC). The majority of participants used a mass balance approach to determine the estradiol content. The key comparison reference value (KCRV) for estradiol in CCQM-K55.a was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. This allowed participants to demonstrate the efficacy (or otherwise) of their implementation of the mass balance approach and to demonstrate that their assigned value for the main component agreed with the KCRV through use of internally consistent contributing methods. The KCRV for the estradiol content of the material was 984.3 mg/g with a combined standard uncertainty of 0.42 mg/g. The individual participant results showed that a relative expanded uncertainty for the purity assignment of 0.2% is a reasonable estimate of the best achievable result by an individual laboratory for a material of this complexity available in this amount at this level of purity. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.2% to 0.8%. The review of results that were biased from the KCRV showed that two major analytical challenges are posed by the material: the measurement of its water content and controlling for related substance artefact formation during the analysis process. The results displaying a positive bias relative to the KCRV (overestimation of estradiol content) were due to underestimation of the water content of the material, while those with a negative bias (underestimation of estradiol) overestimated the total related substance impurities through a failure to detect and control for artefact formation arising from in situ oxidative dimerization of estradiol in neutral solution prior to analysis. There was however good agreement between all participants in the identification and the quantification of the individual related structure impurities actually present in the sample. The comparison also demonstrated the utility of high-field 1H NMR for both quantitative and qualitative analysis of high purity compounds. It is noted that all the participants who used qNMR as a major or contributing technique and included it as part of, combined it or confirmed it with a conventional 'mass balance' data estimate, obtained results consistent with the KCRV. PY - 2012 DO - https://doi.org/10.1088/0026-1394/49/1A/08009 SN - 0026-1394 SN - 1681-7575 VL - 49 IS - 1A Tech. Suppl. / 08009 SP - 1 EP - 33 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-26411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Anderhalten, L. A1 - Silva, R. V. A1 - Morr, A. A1 - Wang, S. A1 - Smorodchenko, A. A1 - Saatz, Jessica A1 - Traub, Heike A1 - Mueller, S. A1 - Boehm-Sturm, P. A1 - Rodriguez-Sillke, Y. A1 - Kunkel, D. A1 - Hahndorf, J. A1 - Paul, F. A1 - Taupitz, M. A1 - Sack, I. A1 - Infante-Duarte, C. T1 - Different Impact of Gadopentetate and Gadobutrol on Inflammation-Promoted Retention and Toxicity of Gadolinium Within the Mouse Brain N2 - Objectives: Using a murine model of multiple sclerosis, we previously showed that repeated administration of gadopentetate dimeglumine led to retention of gadolinium (Gd) within cerebellar structures and that this process was enhanced with inflammation. This study aimed to compare the kinetics and retention profiles of Gd in inflamed and healthy brains after application of the macrocyclic Gd-based contrast agent (GBCA) gadobutrol or the linear GBCA gadopentetate. Moreover, potential Gd-induced neurotoxicity was investigated in living hippocampal slices ex vivo. Materials and Methods: Mice at peak of experimental autoimmune encephalomyelitis (EAE; n = 29) and healthy control mice (HC; n = 24) were exposed to a cumulative dose of 20 mmol/kg bodyweight of either gadopentetate dimeglumine or gadobutrol (8 injections of 2.5 mmol/kg over 10 days). Magnetic resonance imaging (7 T) was performed at baseline as well as at day 1, 10, and 40 post final injection (pfi) of GBCAs. Mice were sacrificed after magnetic resonance imaging and brain and blood Gd content was assessed by laser ablation-inductively coupled plasma (ICP)-mass spectrometry (MS) and ICP-MS, respectively. In addition, using chronic organotypic hippocampal slice cultures, Gd-induced neurotoxicity was addressed in living brain tissue ex vivo, both under control or inflammatory (tumor necrosis factor α [TNF-α] at 50 ng/μL) conditions. Results: Neuroinflammation promoted a significant decrease in T1 relaxation times after multiple injections of both GBCAs as shown by quantitative T1 mapping of EAE brains compared with HC. This corresponded to higher Gd retention within the EAE brains at 1, 10, and 40 days pfi as determined by laser ablation-ICP-MS. In inflamed cerebellum, in particular in the deep cerebellar nuclei (CN), elevated Gd retention was observed until day 40 after last gadopentetate application (CN: EAE vs HC, 55.06 ± 0.16 μM vs 30.44 ± 4.43 μM). In contrast, gadobutrol application led to a rather diffuse Gd content in the inflamed brains, which strongly diminished until day 40 (CN: EAE vs HC, 0.38 ± 0.08 μM vs 0.17 ± 0.03 μM). The analysis of cytotoxic effects of both GBCAs using living brain tissue revealed an elevated cell death rate after incubation with gadopentetate but not gadobutrol at 50 mM. The cytotoxic effect due to gadopentetate increased in the presence of the inflammatory mediator TNF-α (with vs without TNF-α, 3.15% ± 1.18% vs 2.17% ± 1.14%; P = 0.0345). Conclusions: In the EAE model, neuroinflammation promoted increased Gd retention in the brain for both GBCAs. Whereas in the inflamed brains, efficient clearance of macrocyclic gadobutrol during the investigated time period was observed, the Gd retention after application of linear gadopentetate persisted over the entire observational period. Gadopentetate but not gadubutrol appeared to be neurotoxic in an ex vivo paradigm of neuronal inflammation. KW - Imaging KW - ICP-MS KW - Gadolinium KW - Contrast agent KW - Laser ablation KW - Brain KW - Multiple sclerosis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546910 DO - https://doi.org/10.1097/RLI.0000000000000884 SN - 0020-9996/22/0000–0000 VL - 57 IS - 10 SP - 677 EP - 688 PB - Wolters Kluwer N.V. CY - Alphen aan den Rijn, The Netherlands AN - OPUS4-54691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, S. A1 - Kimani, Martha Wamaitha A1 - Zhang, Y. A1 - Verhassel, A. A1 - Sternbæk, L. A1 - Wang, T. A1 - Persson, J. L. A1 - Härkönen, P. A1 - Johansson, E. A1 - Caraballo, R. A1 - Elofsson, M. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Ohlsson, L. A1 - El-Schich, Z. A1 - Gjörloff Wingren, A. A1 - Stollenwerk, M. M. T1 - Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-coated Polystyrene Cores - Assessment of the Binding Behavior to Cancer Cells N2 - Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA. However, these protein molecules are usually expensive and easily denatured, which calls for the development of alternative glycan-specific receptors and cell imaging technologies. In this study, SA-imprinted fluorescent core-shell molecularly imprinted polymer particles (SA-MIPs) were employed to recognize SA on the cell surface of cancer cell lines. The SA-MIPs improved suspensibility and scattering properties compared with previously used core-shell SA-MIPs. Although SA-imprinting was performed using SA without preference for the alpha-2,3- and alpha-2,6-SA forms, we screened the cancer cell lines analyzed using the lectins Maackia Amurensis Lectin I (MAL I, alpha-2,3-SA) and Sambucus Nigra Lectin (SNA, alpha-2,6-SA). Our results show that the selected cancer cell lines in this study presented a varied binding behavior with the SA-MIPs. The binding pattern of the lectins was also demonstrated. Moreover, two different pentavalent SA conjugates were used to inhibit the binding of the SA-MIPs to breast, skin, and lung cancer cell lines, demonstrating the specificity of the SA-MIPs in both flow cytometry and confocal fluorescence microscopy. We concluded that the synthesized SA-MIPs might be a powerful future tool in the diagnostic analysis of various cancer cells. KW - Cancer KW - Imprinting KW - Molecularly imprinted polymers KW - SA conjugates KW - Sialic acid PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546625 DO - https://doi.org/110.3390/cancers14081875 SN - 2072-6694 VL - 14 IS - 8 PB - MDPI CY - Basel AN - OPUS4-54662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pu, Y. A1 - Lawrence, M. J. A1 - Celorrio, V. A1 - Wang, Q. A1 - Gu, M. A1 - Sun, Z. A1 - Agudo Jácome, Leonardo A1 - Russell, A. E. A1 - Huang, L. A1 - Rodriguez, P. T1 - Nickel confined in 2D earth-abundant oxide layers for highly efficient and durable oxygen evolution catalysts N2 - Low cost, high-efficiency catalysts towards water splitting are urgently required to fulfil the increasing demand for energy. In this work, low-loading (<20 wt%) Ni-confined in layered metal oxide anode catalysts (birnessite and lepidocrocite titanate) have been synthesized by facile ion exchange methodology and subjected to systematic electrochemical studies. It was found that Ni-intercalated on K-rich birnessite (Ni-KMO) presents an onset overpotential (ηonset) as low as 100 mV and overpotential at 10 mA cm−2 (η10) of 206 mV in pH = 14 electrolyte. By combining electrochemical methods and X-ray absorption and emission spectroscopies (XAS and XES), we demonstrate Ni sites are the active sites for OER catalysis and that the Mn3+ sites facilitate Ni intercalation during the ion-exchange process, but display no observable contribution towards OER activity. The effect of the pH and the nature of the supporting electrolyte on the electrochemical performance was also evaluated. KW - Confined catalyst KW - Low-loading KW - Layered manganese oxide KW - Oxygen evolution reaction KW - Transmission electron microscopy (TEM) PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515027 DO - https://doi.org/10.1039/D0TA04031B SN - 2050-7496 SN - 2050-7488 VL - 8 IS - 26 SP - 13340 EP - 13350 PB - Royal Society of Chemistry CY - London AN - OPUS4-51502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Wang, Cui A1 - You, Y. A1 - Förster, C. A1 - Schubert, H. A1 - Heinze, K. A1 - Seitz, M. T1 - NIR-NIR-Aufkonvertierung in molekularen Chrom-Ytterbium-Salzen N2 - Photonen-Aufkonvertierung in hetero-oligonuklearen, Metallkomplex-Architekturen mit organischen Liganden ist ein interessantes, aber bisher selten beobachtetes Phänomen, trotz des großen Potentials sowohl aus Sicht der Grundlagenforschung als auch aus der Anwendungsperspektive. Nun wurde ein neues photonisches Material aus molekularen Chrom(III)- und Ytterbium(III)-Komplexionen entwickelt. Dieses zeigt im Festkörper bei Raumtemperatur abhängig von der Anregungsleistungsdichte nach Anregung des 2F7/2! 2F5/2-3berganges des Ytterbiums bei ca. 980 nm eine kooperative Sensibilisierung der Chrom(III)-zentrierten 2E/2T1-Phosphoreszenz bei ca. 775 nm. Der Aufkonvertierungsprozess ist unempfindlich gegenüber Luftsauerstoff und kann in Gegenwart von Wassermolekülen im Kristallgitter beobachtet werden. KW - Crystal KW - Sensor KW - NIR KW - Yb(III) complex KW - Cr(III) KW - Upconversion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517217 DO - https://doi.org/10.1002/ange.202007200 VL - 132 IS - 42 SP - 18804 EP - 18808 PB - Angewandte Chemie AN - OPUS4-51721 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Liu, Y. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Long, W. A1 - Ou, J. T1 - NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ Upconversion Nanoparticles for Optical Temperature Monitoring and Self-Heating in Photothermal Therapy N2 - The core−shell NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ upconversion nanoparticles were successfully prepared by a solvothermal method, and a layer of mesoporous silica (mSiO2) was successfully coated on the periphery of the core−shell nanoparticles to transform their surface from lipophilic to hydrophilic, further expanding their applications in biological tissues. The physical phase, morphology, structure, and fluorescence properties were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (TEM), Fourier infrared spectroscopy (FT-IR), ζ potential analysis, and fluorescence spectroscopy. It was found that the material has a hexagonal structure with good hydrophilicity and emits intense fluorescence under 980 nm pump laser excitation. The non-contact temperature sensing performance of nanoparticles was evaluated by analyzing the upconversion fluorescence of Tm3+ (1G4 → 3F4 and 3F3 → 3H6) in the temperature range of 284−344 K. The absolute and relative sensitivities were found to be 0.0067 K−1 and 1.08 % K−1, respectively, with high-temperature measurement reliability and good temperature cycling performance. More importantly, its temperature measurement in phosphate-buffered saline (PBS) solution is accurate. In addition, the temperature of the cells can be increased by adjusting the laser power density and laser irradiation time. Therefore, an optical temperature sensing platform was built to realize the application of real-time monitoring of cancer cell temperature and the dual function of photothermal therapy. KW - Sensor KW - Temperature KW - Lanthanide KW - Tag KW - Fluorescence KW - Nanoparticles KW - Synthesis KW - Environment KW - Monitoring KW - Sensing KW - Nano KW - Life sciences KW - Upconversion PY - 2023 DO - https://doi.org/10.1021/acsanm.2c05110 VL - 6 IS - 1 SP - 759 EP - 771 PB - ACS Publications AN - OPUS4-57081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Choteau, T. A1 - Daireaux, A. A1 - Wielgosz, R. A1 - Davies, S. A1 - Moad, M. A1 - Chan, B. A1 - Munoz, A. A1 - Conneely, P. A1 - Ricci, M. A1 - Do Rego, E.C.P. A1 - Garrido, B.C. A1 - Violante, F.G.M. A1 - Windust, A. A1 - Dai, X. A1 - Huang, T. A1 - Zhang, W. A1 - Su, F. A1 - Quan, C. A1 - Wang, H. A1 - Lo, M. A1 - Wong, W. A1 - Gantois, F. A1 - Lalerle, B. A1 - Dorgerloh, Ute A1 - Koch, Matthias A1 - Klyk-Seitz, Urszula-Anna A1 - Pfeifer, Dietmar A1 - Philipp, Rosemarie A1 - Piechotta, Christian A1 - Recknagel, Sebastian A1 - Rothe, Robert A1 - Yamazaki, T. A1 - Zakaria, O. B. A1 - Castro, E. A1 - Balderas, M. A1 - González, N. A1 - Salazar, C. A1 - Regalado, L. A1 - Valle, E. A1 - Rodríguez, L. A1 - Laguna, L.Á.. A1 - Ramírez, P. A1 - Avila, M. A1 - Ibarra, J. A1 - Valle, L. A1 - Arce, M. A1 - Mitani, Y. A1 - Konopelko, L. A1 - Krylov, A. A1 - Lopushanskaya, E. A1 - Lin, T.T. A1 - Liu, Q. A1 - Kooi, L.T. A1 - Fernandes-Whaley, M. A1 - Prevoo-Franzsen, D. A1 - Nhlapo, N. A1 - Visser, R. A1 - Kim, B. A1 - Lee, H. A1 - Kankaew, P. A1 - Pookrod, P. A1 - Sudsiri, N. A1 - Shearman, K. A1 - Gören, A.C. A1 - Bilsel, G. A1 - Yilmaz, H. A1 - Bilsel, M. A1 - Cergel, M. A1 - Coskun, F.G. A1 - Uysal, E. A1 - Gündüz, S. A1 - Ün, I. A1 - Warren, J. A1 - Bearden, D.W. A1 - Bedner, M. A1 - Duewer, D.L. A1 - Lang, B.E. A1 - Lippa, K.A. A1 - Schantz, M.M. A1 - Sieber, J.R. T1 - Final report on key comparison CCQM-K55.c (L-(+)-Valine): Characterization of organic substances for chemical purity N2 - KEY COMPARISON Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.c, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2012. Twenty National Measurement Institutes or Designated Institutes and the BIPM participated. Participants were required to assign the mass fraction of valine present as the main component in the comparison sample for CCQM-K55.c. The comparison samples were prepared from analytical grade L-valine purchased from a commercial supplier and used as provided without further treatment or purification. Valine was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of low structural complexity [molecular weight range 100–300] and high polarity (pKOW > –2). The KCRV for the valine content of the material was 992.0 mg/g with a combined standard uncertainty of 0.3 mg/g. The key comparison reference value (KCRV) was assigned by combination of KCRVs assigned from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 1 mg/g to 6 mg/g when using mass balance based approaches alone, 2 mg/g to 7 mg/g using quantitative 1H NMR (qNMR) based approaches and from 1 mg/g to 2.5 mg/g when a result obtained by a mass balance method was combined with a separate qNMR result. The material provided several analytical challenges. In addition to the need to identify and quantify various related amino acid impurities including leucine, isoleucine, alanine and a-amino butyrate, care was required to select appropriate conditions for performing Karl Fischer titration assay for water content to avoid bias due to in situ formation of water by self-condensation under the assay conditions. It also proved to be a challenging compound for purity assignment by qNMR techniques. There was overall excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content, residual solvent and total non-volatile content of the sample. Appropriate technical justifications were developed to rationalise observed discrepancies in the limited cases where methodology differences led to inconsistent results. The comparison demonstrated that to perform a qNMR purity assignment the selection of appropriate parameters and an understanding of their potential influence on the assigned value is critical for reliable implementation of the method, particularly when one or more of the peaks to be quantified consist of complex multiplet signals. PY - 2014 DO - https://doi.org/10.1088/0026-1394/51/1A/08010 SN - 0026-1394 SN - 1681-7575 VL - 51 SP - 08010, 1 EP - 44 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-31072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y. A1 - Ulbricht, Alexander A1 - Schmidt, F. A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Schwitalla, A.D. T1 - Micro-CT analysis and mechanical properties of low dimensional CFR-PEEK specimens additively manufactured by material extrusion N2 - Material extrusion of thermoplastic polymers enables the realization of complex specific designs with high performance composites. The present study aims at evaluating the mechanical properties of carbon fiberreinforced semi-crystalline thermoplastic polymer polyether ether ketone (CFR-PEEK) manufactured by material extrusion and correlating them with results obtained by micro-CT. Samples in the shape of small bars were provided by Kumovis (Munich, Germany). The determination of surface roughness and density was followed by three-point bending tests. To reveal the pore distribution as well as the fusion quality of CFR PEEK when applied with external forces, micro-CT scans were performed with an X-ray microscope before and after the mechanical test to localize the sites where the fracture is generated. The density of CFR-PEEK bars indicated that they had superior mechanical properties compared with our previous study on unfilled 3D printed PEEK (bending modulus: (5.4 ± 0.5) GPa vs. (1.05 ± 0.05) GPa to (1.48 ± 0.10) GPa; bending strength: (167 ± 11) MPa vs. (51 ± 15) to (193 ± 7) MPa). Micro-CT analyses revealed the local 3D-distribution of voids. Voids of 30 μm diameter are nearly spherical and make up the main part of the total porosity. The larger the voids, the more they deviate from a spherical shape. Significant lack-of-fusion voids are located between the deposited filaments. By growing and merging, they act as seeds for the forming fracture line in the region of the flexural specimens where the maximum local tensile stresses occurred under bending load. Our work provides a detailed analysis of printed PEEK with fiber additive and relates this with mechanical properties. KW - CFR-PEEK KW - Material extrusion (MEX) KW - FFF KW - Surface topography KW - Bending property KW - Micro-CT PY - 2023 DO - https://doi.org/10.1016/j.jmbbm.2023.106085 SN - 1751-6161 VL - 146 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-58112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, C. A1 - Tian, X. A1 - Wang, L. A1 - Liu, Y. A1 - Wirth, Cynthia A1 - Günster, Jens A1 - Li, D. A1 - Jin, Z. T1 - Effect of particle size gradation on the performance of glass-ceramic 3D printing process N2 - Particle size gradation is regarded as an effective method for overcoming the contradicting requirements in three-dimensional printing (3DP). In present work, particle size gradation was optimized to obtain both acceptable flowability of the powder material and high-strength 3D-printed glass-ceramic products. The effect of gradation on the printing process, sintering process and performance of the 3D-printed glass-ceramic products was investigated comprehensively. The glass-ceramic powders with three size ranges were mixed in certain proportions and applied to print parts. The result showed parts printed with powder mixed by 60 wt% 45–100 µm and 40 wt% 0–25 µm particles had satisfactory density of 1.60 g/cm³ and bending strength of 13.8 MPa. The flowability decreased with an increasing proportion of fine particles. Part density was determined by the powder bulk density in the powder bed as well as the shrinkage during sintering while strength of part was found to be dependent on the sintering degree. KW - Flowability KW - Glass-ceramic KW - Particle size gradation KW - Three-dimensional printing KW - Mechanical properties PY - 2017 DO - https://doi.org/10.1016/j.ceramint.2016.09.197 SN - 0272-8842 VL - 43 IS - 1 SP - 578 EP - 584 PB - Elsevier AN - OPUS4-39783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ji, Y. A1 - Mezhov, Alexander A1 - Wang, S. A1 - Stephan, D. T1 - Influence of polycarboxylate superplasticizers with different molecular structures on rheological properties of glass bead suspension at different resting times N2 - Using an inert glass bead suspension, the study explores the interaction between various PCE superplasticizers, ions and investigates how it affects rheological performance during resting. To understand the underlying mechanisms, surface charge properties, adsorption, aggregates amount, and size of PCE during resting were measured. Results showed that yield stress increased with time, mainly when a high PCE dosage was used, and the modulus from strain sweep experiments agreed with the yield stress variations. The increase in zeta potential value and decrease in aggregate amount explain the decrease in yield stress in the non-PCE sample but are inconsistent with the increase in yield stress in presence of PCE. The PCE clusters’ size increases during resting, and increasing PCE adsorption does not disperse the glass bead particles. In addition, compared to the amount of carboxylate group, the molecular weight of PCE is more dominant in increasing the yield stress during resting. The increase in yield stress could be explained by the increase in the bridging and depletion forces due to the increasing size of the PCE cluster. Another possible reason is that non-adsorbed PCE clusters may form a polymer network that restricts the movement of the particles. KW - Glass bead KW - Rheological performance KW - PCE superplasticizers KW - Ion KW - Resting time PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617609 DO - https://doi.org/10.1016/j.colsurfa.2024.133583 SN - 0927-7757 VL - 688 IS - 133583 SP - 1 EP - 12 PB - Elsevier B.V. CY - Schweiz AN - OPUS4-61760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ren, J. A1 - Weigert, Florian A1 - Weber, F. A1 - Wang, Y. A1 - Choudhury, S. A1 - Xiao, J. A1 - Lauermann, I. A1 - Resch-Genger, Ute A1 - Bande, A. A1 - Petit, T. ED - Petit, Tristan T1 - Influence of surface chemistry on optical, chemical and electronic properties of blue luminescent carbon dots N2 - Carbon dots have attracted much attention due to their unique optical, chemical and electronic properties enabling a wide range of applications. The properties of carbon dots can be effectively adjusted through modifying their chemical composition. However, a major challenge remains in understanding the core and surface contributions to optical and electronic transitions. Here, three blue luminescent carbon dots with carboxyl, amino and hydroxyl groups were comprehensively characterized by UV-vis absorption and emission spectroscopy, synchrotron-based X-ray spectroscopy, and infrared spectroscopy. The influence of the surface functionality on their fluorescence was probed by pH-dependent photoluminescence measurements. Moreover, the hydrogen bonding interactions between water and the surface groups of carbon dots were characterized by infrared spectroscopy. Our results show that both core and surface electronic states of blue luminescent carbon dots contribute to electronic acceptor levels while the chemical nature of the surface groups determines the hydrogen bonding behavior of the carbon dots. This comprehensive spectroscopic study demonstrates that the surface chemistry has a profound influence on the electronic configuration and surface–water interaction of carbon dots, thus affecting their photoluminescence properties. KW - Quantum dots KW - Spectroscopy KW - UV Vis KW - Fluorescence KW - Surface chemistry PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472325 DO - https://doi.org/10.1039/c8nr08595a SN - 2040-3372 VL - 11 IS - 4 SP - 2056 EP - 2064 PB - RSC AN - OPUS4-47232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gao, S. A1 - Hou, J. A1 - Deng, Z. A1 - Wang, T. A1 - Beyer, Sebastian A1 - de Oliveira Guilherme Buzanich, Ana A1 - Richardson, J. J. A1 - Rawal, A. A1 - Seidel, R. A1 - Zulkifli, M. Y. A1 - Li, W. A1 - Bennett, T. D. A1 - Cheetham, A. K. A1 - Liang, K. T1 - Improving the Acidic Stability of Zeolitic Imidazolate Frameworks by Biofunctional Molecules N2 - Zeolitic imidazolate frameworks (ZIFs) have been widely investigated for their use in separation, gas adsorption, catalysis, and biotechnology. Their practical applications, however, can be hampered by their structural instability in humid acidic conditions. Here, guided by density functional theory calculations, we demonstrate that the acidic stability of two polymorphic ZIFs (i.e., ZIF-8 and ZIF-L) can be enhanced by the incorporation of functional groups on polypeptides or DNA. A range of complementary synchrotron investigations into the local chemical structure and bonding environment suggest that the enhanced acidic stability arises from the newly established coordinative interactions between the Zn centers and the inserted carboxylate (for polypeptides) or phosphate (for DNA) groups, both of which have lower pKas than the imidazolate ligand. With functional biomolecular homologs (i.e., enzymes), we demonstrate a symbiotic stability reinforcement effect, i.e., the encapsulated biomolecules stabilize the ZIF matrix while the ZIF exoskeleton protects the enzyme from denaturation. KW - Zeolitic Imidazolate Frameworks KW - Biofunctional Molecules KW - X-ray Absorption Spectroscopy PY - 2019 DO - https://doi.org/10.1016/j.chempr.2019.03.025 VL - 5 IS - 6 SP - 1597 EP - 1608 PB - Elsevier Inc. AN - OPUS4-48702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pu, Y. A1 - Celorrio, V. A1 - Stockmann, Jörg Manfred A1 - Sobol, Oded A1 - Sun, Z. A1 - Wang, W. A1 - Lawrence, M. J. A1 - Radnik, Jörg A1 - Russel, A. E. A1 - Hodoroaba, Vasile-Dan A1 - Huang, L. A1 - Rodriguez, P. T1 - Surface galvanic formation of Co-OH on Birnessite and its catalytic activity for the oxygen evolution reaction N2 - Low-cost, high-efficient catalysts for water splitting can be potentially fulfilled by developing earthabundant metal oxides. In this work, surface galvanic formation of Co-OH on K0.45MnO2 (KMO) was achieved via the redox reaction of hydrated Co2+ with crystalline Mn4+. The synthesis method takes place at ambient temperature without using any surfactant agent or organic solvent, providing a clean, green route for the design of highly efficient catalysts. The redox reaction resulted in the formation of ultrathin Co-OH nanoflakes with high electrochemical surface area. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the changes in the oxidation state of the bulk and surface species on the Co-OH nanoflakes supported on the KMO. The effect of the anions, such as chloride, nitrate and sulfate, on the preparation of the catalyst was evaluated by electrochemical and spectrochemical means. XPS and Time of flight secondary ion mass spectrometry (ToF-SIMS) analysis demonstrated that the layer of CoOxHy deposited on the KMO and its electronic structure strongly depend on the anion of the precursor used during the synthesis of the catalyst. In particular, it was found that Cl- favors the formation of Co-OH, changing the rate-determining step of the reaction, which enhances the catalytic activity towards the OER, producing the most active OER catalyst in alkaline media. KW - Nanoparticles KW - Oxygen evolution reaction (OER) KW - Catalysis KW - ToF-SIMS KW - XPS KW - K-rich Birnessite (K0.45MnO2) PY - 2021 DO - https://doi.org/10.1016/j.jcat.2021.02.025 VL - 396 SP - 304 EP - 314 PB - Elsevier Inc. AN - OPUS4-52328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xing, H. A1 - Jing, H. A1 - Dong, X. A1 - Wang, Lei A1 - Han, Y. A1 - Hu, R. T1 - Cellular growth during rapid directional solidification: Insights from quantitative phase field simulations N2 - In this paper, columnar cellular growth with kinetic effects including kinetic undercooling and solute trapping in rapid directional solidification of alloys was investigated by using a recent quantitative phase-field model for rapid solidification. Morphological transition and primary spacing selection with and without kinetic effects were numerically investigated. Numerical results show that doublon structure is an intermediate state in the primary spacing adjustment of cellular arrays. It was found that the inclusions of kinetic effects result in the increase of the solute in the solid phase and the solute enrichment in the interdendritic liquid channel. Moreover, predicted results indicate that the growth directions of the cellular arrays in rapid directional solidification with and without kinetic effects are independent of the Péclet number. Therefore, the kinetic effects play important roles in numerical simulations of the growth pattern selection and solute distribution during rapid solidification. Neglecting them will result in the inaccurately predicted results. KW - Rapid solidification KW - Phase-field model PY - 2022 DO - https://doi.org/10.1016/j.mtcomm.2022.103170 VL - 30 SP - 103170 PB - Elsevier Ltd. AN - OPUS4-54571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Westwood, S. A1 - Josephs, R. D. A1 - Choteau, T. A1 - Martos, G. A1 - Wielgosz, R. A1 - Sarzuri, Y. A. A1 - Mendoza, E. A1 - do Rego, E. C. P. A1 - Violante, F. G. M. A1 - da Silva Souza, W. A1 - de Carvalho, L. J. A1 - Fernandes, J. L. N. A1 - Bates, J. A1 - Rajotte, I. A1 - Melanson, J. E. A1 - Li, H. A1 - Guo, Z. A1 - Su, F. A1 - Wang, S. A1 - Huang, T. A1 - Lalerle, B. A1 - Gantois, F. A1 - Piechotta, Christian A1 - Philipp, Rosemarie A1 - Kaminski, Katja A1 - Klyk-Seitz, Urzsula-Anna A1 - Giannikopoulou, P. A1 - Skotidaki, E. A1 - Kakoulides, E. A1 - Pui-Kwan, C. A1 - Kuroe, M. A1 - Itoh, N. A1 - Calderón, M. A. A. A1 - Contreras, L. R. A1 - Osuna, M. A. A1 - Alrashed, M. A1 - Ting, L. A1 - Mei, G. E. A1 - Juan, W. A1 - Sze, C. P. A1 - Lin, T. T. A1 - Quinn, L. A1 - Swiegelaar, C. A1 - Fernandes-Whaley, M. A1 - Ahn, S. A1 - Chaiphet, T. A1 - Sudsiri, N. A1 - Bellazreg, W. A1 - Bilsel, M. A1 - Colombo, G. T1 - Key comparison CCQM-K78.b - non-polar analytes in organic solvent: methoxychlor and trifluralin in acetonitrile N2 - The CCQM-K78.b key comparison was coordinated by the Bureau International des Poids et Mesures (BIPM) on behalf of the CCQM Organic Analysis Working Group (OAWG) of the 'Comité Consultatif pour la Quantité de Matière' (CCQM), for National Measurement Institutes (NMIs) and Designated Institutes (DIs) providing measurement services in organic analysis under the 'Comité International des Poids et Mesures' (CIPM) Mutual Recognition Arrangement (MRA). This key comparison was conducted as a 'Track A' comparison within the OAWG's 10-year strategic plan. The goal of CCQM-K78.b was to underpin capabilities for the value assignment of calibration solutions containing low polarity/non-polar organic analytes in organic solvents. The selected model system consisted of a two-component pesticide solution in acetonitrile, comprising methoxychlor and trifluralin. Participants were tasked with assigning the mass fractions, in units of μg/g, of methoxychlor and trifluralin in acetonitrile solution. The mass fraction levels and analytical challenges of the selected analytes were representative of those encountered for calibration solutions of non-polar organic analytes. Participation in CCQM-K78.b allowed for the benchmarking of capabilities for assigning the mass fraction of non-polar organic compounds (pKow < -2) in solution, at mass fractions above 5 μg/g, in an organic solvent. Additionally, the comparison assessed the capabilities for the quantitative assignment of thermally labile compounds. Participants were provided by the BIPM with ampoules containing methoxychlor and trifluralin in acetonitrile. Each participant reported the mass fraction content of each analyte in μg/g. All participants ensured the metrological traceability of their results through the use of a Primary Reference Material (PRM), which was used to prepare a primary calibrator solution for each analyte using a gravimetric procedure. The twenty participating institutes primarily used analysis procedures based on GC-MS, -IDMS, -MS/MS, -ECD, and -FID, with some participants also using LC-UV for the value assignment. The analysis of methoxychlor and trifluralin in acetonitrile solution presented several challenges, including the thermal stability of the analytes under selected analytical techniques, control of solvent volatility, and considerable variation in some results using MS-based quantification methods. The mass fraction assignments for methoxychlor and trifluralin, consistent with the key comparison reference values (KCRVs), were achieved with associated relative standard uncertainties of (0.38 - 2.9) % for methoxychlor and (0.35 - 2.5) % for trifluralin. 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 https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA). KW - Methoxychlor KW - Trifluralin KW - CCQM KW - Key comparison PY - 2025 DO - https://doi.org/10.1088/0026-1394/62/1A/08010 SN - 0026-1394 VL - 62 IS - 1A SP - 1 EP - 37 PB - IOP Publishing AN - OPUS4-64691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Purohit, Purv A1 - Wang, D.-Y. A1 - Wurm, Andreas A1 - Schick, C. A1 - Schönhals, Andreas T1 - Comparison of thermal and dielectric spectroscopy for nanocomposites based on polypropylene and layered double hydroxide - proof of interfaces N2 - Polymer based nanocomposites by melt blending of synthesized ZnAl-Layered Double Hydroxide (ZnAl-LDH) and polypropylene (PP) were investigated by temperature modulated differential scanning calorimetry (TMDSC). The LDH was organically modified by using a surfactant, sodium dodecylbenzene sulfonate (SDBS) to increase the interlayer spacing of the LDH, so that polymer segments can intercalate the inter layer galleries. The glass transition temperature (Tg) and the thermal relaxation strength (Δcp) were determined. The Tg remains constant for concentration till 12 wt% of LDH and a slight reduction of 3 K might be observed for 16 wt% LDH but within the experimental error. The thermal relaxation strength decreases indicating reduction in the amount of mobile polymer segments from amorphous fraction. This finding is supported by the increase in the rigid amorphous fraction (RAF) which is attributed to the polymer molecules which are in close proximity to the crystals and the LDH sheets, as they hinder their mobility. This is analyzed in detail and related to the dielectric relaxation spectroscopy (BDS) results. KW - Polypropylene KW - Layered double hydroxide KW - Nanocomposites KW - Temperature modulated differential scanning calorimetery KW - Dielectric spectroscopy KW - Rigid amorphous fraction PY - 2014 DO - https://doi.org/10.1016/j.eurpolymj.2014.03.005 SN - 0014-3057 SN - 1873-1945 VL - 55 SP - 48 EP - 56 PB - Elsevier CY - Oxford AN - OPUS4-30626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rienitz, O. A1 - Pramann, A. A1 - Vogl, Jochen A1 - Lee, K.-S. A1 - Yim, Y.-H. A1 - Malinovskiy, D. A1 - Hill, S. A1 - Dunn, P. A1 - Goenaga-Infante, H. A1 - Ren, T. A1 - Wang, J. A1 - Vocke jr., R. D. A1 - Rabb, S: A. A1 - Narukawa, T. A1 - Yang, L. A1 - Mester, Z. A1 - Meija, J. A1 - Aref'ev, D. G. A1 - Marchin, V. A1 - Sharin, A. G. A1 - Bulanov, A. D. A1 - Potapov, A. M. A1 - Otopkova, P. A. A1 - Kessel, R. T1 - The comparability of the determination of the molar mass of silicon highly enriched in 28Si: results of the CCQM-P160 interlaboratory comparison and additional external measurements N2 - An international comparison study on the accurate determination of the molar mass M(Si) of silicon artificially enriched in 28Si (x(28Si) > 0.9999 mol mol−1) has been completed. The measurements were part of the high level CCQM-P160 pilot study assessing the ability of National Metrology Institutes (NMIs) and Designated Institutes (DIs) to make such measurements at the lowest possible levels of measurement uncertainty and to identify possible difficulties when measuring this kind of sample. This study supports the molar mass measurements critical to disseminating the silicon route to realizing the new definitions for the kilogram and the mole. Measurements were also made by one external research institute and an external company. The different institutes were free to choose their experimental (mass spectrometric) set-ups and equipment, thereby enabling also the comparison of different techniques. The investigated material was a chemically pure, polycrystalline silicon material. The subsequent modified single crystalline secondary product of this material was intended for the production of silicon which was used for two additional spheres in the context of the redetermination of the Avogadro constant NA, required for the revision of the International System of Units (SI) via fundamental constants which came into force from May 2019. The CCQM pilot study was organized by Physikalisch-Technische Bundesanstalt (PTB). Aqueous silicon solutions were shipped to all participating institutions. The data analysis as well as the uncertainty modelling and calculation of the results was predefined. The participants were provided with an uncertainty budget as a GUM Workbench® file as well as a free software license for the duration of the comparison. The agreement of the values of the molar mass (M(Si) = 27.976 942 577 g mol−1) was excellent with ten out of 11 results reported within the range of relative uncertainty of 1 × 10−8 required for the revision of the SI. KW - Absolute isotope ratio KW - Molar mass KW - Avogadro constant KW - Revision of the SI PY - 2020 DO - https://doi.org/10.1088/1681-7575/abbdbf VL - 57 IS - 6 SP - 065028 PB - IOP Science CY - Cambridge AN - OPUS4-51500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Abbasi, M. A1 - Pauw, Brian Richard A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schick, C. A1 - Saalwächter, K. A1 - Schönhals, Andreas T1 - Spatial inhomogeneity, Interfaces and Complex Vitrification Kinetics in a Network Forming Nanocomposite N2 - A detailed calorimetric study on an epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) as the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) as nanofiller. The -NH2 group of taurine can react with DGEBA improving the interaction of the polymer with the filler. The combined X-ray scattering, and electron microscopy data showed that the nanocomposite has a partially exfoliated morphology. Calorimetric studies were performed with conventional DSC, temperature modulated DSC (TMDSC) and fast scanning calorimetry (FSC) in the temperature modulated approach (TMFSC) to investigate the vitrification and molecular mobility in dependence of the filler concentration. First, TMDSC and NMR were used to estimate the amount of the rigid amorphous fraction which consists of immobilized polymer segments at the nanoparticle surface. It was found to be 40 wt% for the highest filler concentration, indicating that the interface dominates the overall macroscopic properties and behavior of the material to a great extent. Second, the relaxation rates of the α-relaxation obtained by TMDSC and TMFSC were compared with the thermal and dielectric relaxation rates measured by static FSC. The investigation revealed that the system shows two distinct α-relaxation processes. Furthermore, also two separate vitrification mechanisms were found for a bulk network-former without geometrical confinement as also confirmed by NMR. This was discussed in terms of the intrinsic spatial heterogeneity on a molecular scale, which becomes more pronounced with increasing nanofiller content. KW - Polymer based Nanocomposites PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523199 DO - https://doi.org/10.1039/d0sm01992e SN - 1744-6848 VL - 17 IS - 10 SP - 2775 EP - 2790 PB - Royal Society of Chemistry AN - OPUS4-52319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Altenburg, T. A1 - Giese, S. A1 - Wang, S. A1 - Muth, Thilo A1 - Renard, B.Y. T1 - Ad hoc learning of peptide fragmentation from mass spectra enables an interpretable detection of phosphorylated and cross-linked peptides N2 - Mass spectrometry-based proteomics provides a holistic snapshot of the entire protein set of living cells on a molecular level. Currently, only a few deep learning approaches exist that involve peptide fragmentation spectra, which represent partial sequence information of proteins. Commonly, these approaches lack the ability to characterize less studied or even unknown patterns in spectra because of their use of explicit domain knowledge. Here, to elevate unrestricted learning from spectra, we introduce ‘ad hoc learning of fragmentation’ (AHLF), a deep learning model that is end-to-end trained on 19.2 million spectra from several phosphoproteomic datasets. AHLF is interpretable, and we show that peak-level feature importance values and pairwise interactions between peaks are in line with corresponding peptide fragments. We demonstrate our approach by detecting post-translational modifications, specifically protein phosphorylation based on only the fragmentation spectrum without a database search. AHLF increases the area under the receiver operating characteristic curve (AUC) by an average of 9.4% on recent phosphoproteomic data compared with the current state of the art on this task. Furthermore, use of AHLF in rescoring search results increases the number of phosphopeptide identifications by a margin of up to 15.1% at a constant false discovery rate. To show the broad applicability of AHLF, we use transfer learning to also detect cross-linked peptides, as used in protein structure analysis, with an AUC of up to 94%. KW - Mass spectrometry KW - Machine learning KW - Deep learning KW - Peptide identification PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547580 DO - https://doi.org/10.1038/s42256-022-00467-7 SN - 2522-5839 VL - 4 SP - 378 EP - 388 PB - Springer Nature CY - London AN - OPUS4-54758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, Y.-L. A1 - Zheng, A1 - Zhang, A1 - Lu, A1 - Wang, A1 - Kunte, Hans-Jörg A1 - Sand, W. T1 - Forecast on Long Term Chemical Environment Evolution on Surface of Nuclear Waste Container N2 - Surface environment changes of nuclear waste container, mainly including oxygen contents, buffer pore water components and pH under the conditions of “borehole” type and “In-floor” type with bentonite buffer/backfill and concrete buffer were summarized. This summarization provides a basic corrosion environment reference for the corrosion evolution re- search of high-level radioactive waste disposal repository in our country. KW - Corrosion evolution KW - Nuclear waste KW - Disposal repository KW - Corrosion environment PY - 2018 DO - https://doi.org/10.7643/ issn.1672-9242.2018.10.017 SN - 1672-9242 VL - 15 IS - 10 SP - 103 EP - 108 PB - Zhongguo Bingqi Gongye di-wujiu Yanjiusuo CY - Chongqing AN - OPUS4-46952 LA - zho AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen A1 - Yim, Y.-H. A1 - Lee, K.-S. A1 - Goenaga-Infante, H. A1 - Malinowskiy, D. A1 - Ren, T. A1 - Wang, J. A1 - Vocke Jr., R.D. A1 - Murphy, K. A1 - Nonose, N. A1 - Rienitz, O. A1 - Noordmann, J. A1 - Näykki, T. A1 - Sara-Aho, T. A1 - Ari, B. A1 - Cankur, O. T1 - Final report of the key comparison CCQM-K98: Pb isotope amount ratios in bronze KW - CCQM KW - Metrology KW - Isotope amount ratios KW - Lead PY - 2014 UR - http://www.bipm.org/utils/common/pdf/final_reports/QM/K98/CCQM-K98.pdf DO - https://doi.org/10.1088/0026-1394/51/1A/08017 SN - 0026-1394 SN - 1681-7575 VL - 51 IS - 1A Tech. Suppl. SP - 08017-1 EP - 08017-47 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-31929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deng, C. A1 - Yin, Huajie A1 - Li, R.-M. A1 - Huang, S.-C. A1 - Schartel, Bernhard A1 - Wang, Y.-Z. T1 - Modes of action of a mono-component intumescent flame retardant MAPP in polyethylene-octene elastomer N2 - A mono-component intumescent flame retardant named ethylenediamine-modified ammonium polyphosphate (MAPP) is used in polyethylene-octene elastomer (POE). Insight into the flame-retardant mechanisms of the MAPP is provided from a new perspective. The fire performance of POE/MAPP composites is investigated by oxygen index (OI) and vertical burning (UL-94) tests. POE Composite containing 35 wt% MAPP achieves a V-0 rating, and its OI is 29.3 vol%. The thermogravimetric Analysis (TGA) and Fourier transform infrared spectra (FTIR) confirm that the incorporation of ethylenediamine changes the thermal decomposition of APP, mainly resulting in the formation of char layer with a thermally stable structure. Cone calorimeter analysis revealed the flame-retardant modes of action of MAPP in POE under forced-flaming conditions. Quantitative analysis illustrates that both the residue due to charring and the fuel dilution/flame Inhibition resulting from the release of incombustible products/ phosphorus species decrease the total heat release (fire load) by 20e28%. The residue increases linearly with increasing MAPP content, whereas the reduction in effective heat of combustion levels off. Moreover, the flame-retardant effect resulting from the protective properties of the char is discovered to be the dominant mode of action (up to 85% reduction) with respect to the peak heat release rate, leading to the excellent flame retardancy of POE/MAPP. KW - Ammonium polyphosphate KW - Flame retardant KW - Carbonization KW - Elastomer PY - 2017 DO - https://doi.org/10.1016/j.polymdegradstab.2017.03.006 SN - 0141-3910 SN - 1873-2321 VL - 138 SP - 142 EP - 150 PB - Elsevier AN - OPUS4-39901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Vogl, Jochen A1 - Becker, Dorit A1 - Koenig, Maren A1 - Yim, Y.-H. A1 - Lee, K.-S. A1 - Goenaga-Infante, H. A1 - Malinowskiy, D. A1 - Hill, S. A1 - Ren, T. A1 - Wang, J. A1 - Vocke, R. D. A1 - Murphy, K. A1 - Nonose, N. A1 - Rienitz, O. A1 - Noordmann, J. T1 - Certification Report for the Isotopic Reference Materials ERM-AE142 and ERM-EB400 N2 - Lead (Pb) isotope amount ratios are commonly used in applications ranging from archaeology and forensic sciences to terrestrial and extra-terrestrial geochemistry. Despite their utility and frequency of use, only three certified isotope amount ratio reference materials are currently available for Pb: NIST SRMs 981, 982 and 983. Because SRM 981 has a natural Pb isotopic composition, it is mainly used for correcting instrumental mass discrimination or fractionation. This means that, at present, there are no other certified isotope reference materials with natural Pb isotopic composition that could be used for validating or verifying an analytical procedure involving the measurement of Pb isotope amount ratios. To fill this gap, two new reference materials, both certified for their Pb isotopic composition, have been produced together with a complete uncertainty assessment. These new reference materials offer SI traceability and an independent means of validating or verifying analytical procedures used to produce Pb isotope amount ratio measurements. ERM-EB400 is a bronze material containing a nominal Pb mass fraction of 45 mg/kg. ERM-AE142 is a high purity solution of Pb with a nominal mass fraction of 100 mg/kg. Both materials have been specifically produced to assist analysts in verifying or validating their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM-EB400), the other does not (ERM-AE142). Details on the certification of these isotope reference materials are provided in this report. KW - Lead isotopic composition KW - Isotope ratio KW - Reference material KW - Mass spectrometry PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392060 SP - 1 EP - 16 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-39206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Kang, N. A1 - Wang, D.-Y. A1 - Wurm, Andreas A1 - Schick, C. A1 - Schönhals, Andreas T1 - Crystallization behavior of nanocomposites based on poly(L-lactide) and MgAl layered double hydroxides - Unbiased determination of the rigid amorphous phases due to the crystals and the nanofiller N2 - Semicrystalline polymers have to be described by a three phase model consisting of a mobile amorphous (MAF), a crystalline (CF), and a rigid amorphous fraction (RAF). For nanocomposites based on a semicrystalline polymer the RAF is due to both the crystallites (RAFcrystal) and the filler (RAFfiller). Polymer nanocomposite based on poly(L-lactide) and MgAl layered double hydroxide nanofiller were prepared. Due to the low crystallization rate of PLA ist crystallization can be suppressed by a high enough cooling rate, and the RAF is due only to the nanofiller. The MAF, CF, and RAF were estimated by Temperature Modulated DSC. For the first time CF, MAF, RAFcrystal, and RAFfiller could be estimated. It was found, that RAFfiller increases linearly with the concentration of the nanofiller for this system. Furthermore, RAFcrystal is only slightly influenced by the presence of the nanofiller. KW - Polymer based nanocomposites PY - 2017 DO - https://doi.org/10.1016/j.polymer.2016.11.065 SN - 0032-3861 SN - 1873-2291 VL - 108 SP - 257 EP - 264 PB - Elesevier AN - OPUS4-39052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Omar, Hassan A1 - Smales, Glen Jacob A1 - Henning, S. A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Calorimetric and Dielectric Investigations of Epoxy-Based Nanocomposites with Halloysite Nanotubes as Nanofillers N2 - Epoxy nanocomposites are promising materials for industrial applications (i.e., aerospace, marine and automotive industry) due to their extraordinary mechanical and thermal properties. Here, the effect of hollow halloysite nanotubes (HNT) on an epoxy matrix (Ep) was the focus of the study. The structure and molecular mobility of the nanocomposites were investigated using a combination of X-ray scattering, calorimetry (differential (DSC) and fast scanning calorimetry (FSC)) and dielectric spectroscopy. Additionally, the effect of surface modification of HNT (polydopamine (PDA) and Fe(OH)3 nanodots) was considered. For Ep/HNT, the glass transition temperature (Tg) is was de-creased due to a nanoparticle-related decrease of the crosslinking density. For the modified system, Ep/m-HNT, the surface modification resulted in enhanced filler–matrix interactions leading to higher Tg values than the pure epoxy in some cases. For Ep/m-HNT, the amount of interface formed between the nanoparticles and the matrix ranged from 5% to 15%. Through BDS measurements, localized fluctuations were detected as a β- and γ-relaxation, related to rotational fluctuations of phenyl rings and local reorientations of unreacted components. A combination of calorimetry and BDS dielectric spectroscopy revealed a dynamic and structural heterogeneity of the matrix, as confirmed by two glassy dynamics in both systems, related to regions with different crosslinking densities. KW - Rigid amorphous fraction KW - Epoxy nanocomposites KW - Halloysite nanotubes KW - X-ray scattering KW - Differential scanning calorimetry KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526668 DO - https://doi.org/10.3390/polym13101634 VL - 13 IS - 10 SP - 1634 PB - MDPI AN - OPUS4-52666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y.-W. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Dihydronaphthalene-fused Boron-dipyrromethene (BODIPY) dyes: insight into the electronic and conformational tuning modes of BODIPY fluorophones KW - Farbstoffe KW - Fluoreszenz KW - NMR-Spektroskopie KW - Synthese PY - 2012 DO - https://doi.org/10.1002/chem.201201081 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 23 SP - 7306 EP - 7309 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y.-W. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Dihydronaphthalene-fused Boron-dipyrromethene (BODIPY) dyes: insight into the electronic and conformational tuning modes of BODIPY fluorophores N2 - A new series of boron-dipyrromethene (BDP, BODIPY) dyes with dihydronaphthalene units fused to the β-pyrrole positions (1 a-d, 2) has been synthesised and spectroscopically investigated. All the dyes, except pH-responsive 1 d in polar solvents, display intense emission between 550-700 nm. Compounds 1 a and 1 b with a hydrogen atom and a methyl group in the meso position of the BODIPY core show spectroscopic properties that are similar to those of rhodamine 101, thus rendering them potent alternatives to the positively charged rhodamine dyes as stains and labels for less polar environments or for the dyeing of latex beads. Compound 1 d, which carries an electron-donating 4-(dimethylamino)phenyl group in the meso position, shows dual fluorescence in solvents more polar than dibutyl ether and can act as a pH-responsive "light-up" probe for acidic pH. Correlation of the pKa data of 1 d and several other meso-(4-dimethylanilino)-substituted BODIPY derivatives allowed us to draw conclusions on the influence of steric crowding at the meso position on the acidity of the aniline nitrogen atom. Preparation and investigation of 2, which carries a nitrogen instead of a carbon as the meso-bridgehead atom, suggests that the rules of colour tuning of BODIPYs as established so far have to be reassessed; for all the reported couples of meso-C- and meso-N-substituted BODIPYs, the exchange leads to pronounced redshifts of the spectra and reduced fluorescence quantum yields. For 2, when compared with 1 a, the opposite is found: negligible spectral shifts and enhanced fluorescence. Additional X-ray crystallographic analysis of 1 a and quantum chemical modelling of the title and related compounds employing density functional theory granted further insight into the features of such sterically crowded chromophores. KW - Dyes/pigments KW - Fluorescent probes KW - Photophysics KW - Protonation KW - Boron PY - 2010 DO - https://doi.org/10.1002/chem.200902527 SN - 0947-6539 SN - 1521-3765 VL - 16 IS - 9 SP - 2887 EP - 2903 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-20957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, X. A1 - Zhang, J. A1 - Wang, H. A1 - Rogal, J: A1 - Li, H.-Y. A1 - Wei, S.-H. A1 - Hickel, Tilmann T1 - Defect-characterized phase transition kinetics N2 - Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field. KW - Kinetics KW - Atomistic models KW - Phase transitions KW - Defects PY - 2022 DO - https://doi.org/10.1063/5.0117234 SN - 1931-9401 VL - 9 IS - 4 SP - 1 EP - 42 PB - AIP CY - New York, NY AN - OPUS4-56507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schoenhals, Andreas T1 - Dielectric and flash DSC investigations on an epoxy based nanocomposite system with MgAl layered double hydroxide as nanofiller N2 - Nanocomposites based on MgAL layered double hydroxides (LDH) and an epoxy resin were prepared and investigated by a combination of complementary methods. As epoxy resin Bisphenol A diglycidyl ether (DGEBA) was used with Diethylenetriamine as curing agent. The LDH was modified with taurine, which acts as an additional crosslinking agent due to its amine groups. The epoxy resin was cured in a presence of the nanofiller, which was added to the system in various concentrations. X-ray scattering, by combination of SAXS and WAXS was used to characterize the morphology of the obtained nanocomposites. These investigations show that the filler is distributed in the matrix as small stacks of ca. 10 layers. The molecular dynamics of the system, as probe for structure, was investigated by broadband dielectric spectroscopy. In addition to the - and -relaxation (dynamic glass transition), characteristic for the unfilled materials, a further process was found which was assigned to localized fluctuations of segments physically adsorbed or chemically bonded to the nanoparticles. The dielectric -relaxation is shifted to higher temperatures for the nanocomposites in comparison to the pure material but depends weakly on the content of nanoparticles. Further, for the first time Flash DSC was employed to a thermosetting system to investigate the glass transition behavior of the nanocomposites. The heating rates were converted in to relaxation rates. For low concentrations of the nanofiller the thermal data overlap more or less with that of the pure epoxy. For higher concentrations the thermal data are shifted significantly to higher temperatures. This is discussed in terms the cooperativity approach to the glass transition. KW - Nanocomposites KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2019 DO - https://doi.org/10.1016/j.tca.2019.01.010 SN - 0040-6031 VL - 677 SP - 151 EP - 161 PB - Elsevier AN - OPUS4-48218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen A1 - Yim, Y.-H. A1 - Lee, K.-S. A1 - Goenaga-Infante, H A1 - Malinovskiy, D. A1 - Hill, S. A1 - Ren, T. A1 - Wang, J. A1 - Vocke, R. D. A1 - Murphy, K. E. A1 - Nonose, N. A1 - Rienitz, O. A1 - Noordmann, J. T1 - Certification of ERM-EB400, the first matrix reference material for lead isotope amount ratios, and ERM-AE142, a lead solution providing a lead isotopic composition at the edge of natural variation N2 - Lead isotope amount ratios are commonly used in diverse fields such as archaeometry, geochemistry and forensic science. Currently, five reference materials with certified lead isotope amount ratios are available, namely NIST SRM 981, 982 and 983, GBW-04442 and NMIJ 3681-a. Only NIST SRM 981 and NMIJ 3681-a have approximately natural isotopic compositions, and NIST SRM 981 is predominantly used for correcting mass discrimination/mass fractionation in the applied mass spectrometric procedures. Consequently, there is no other certified reference material available to be used for validation and/or quality control of the analytical procedures applied to lead isotope amount ratio measurements. To fill this gap, two new reference materials have been produced and certified for their lead isotope amount ratios. For both certified reference materials, complete uncertainty budgets have been calculated and SI traceability has been established. This provides the users with independent means for validating and verifying their analytical procedures and for conducting quality control measures. ERM-EB400 is a bronze material with a nominal lead mass fraction of 45 mg kg-1 and certified lead isotope amount ratios of n(206Pb)/n(204Pb) = 18.072(17) mol mol-1, n(207Pb)/n(204Pb) = 15.578(18) mol mol-1 and n(208Pb)/n(204Pb) = 38.075(46) mol mol-1 with the associated expanded uncertainties (k = 2) given in brackets. ERM-AE142 is a high-purity solution of lead in 2% nitric acid with a nominal mass fraction of 100 mg kg-1 and certified Pb isotope amount ratios of n(206Pb)/n(204Pb) = 21.114(17) mol mol-1, n(207Pb)/n(204Pb) = 15.944(17) mol mol-1 and n(208Pb)/n(204Pb) = 39.850(44) mol mol-1 with the associated expanded uncertainties (k = 2) given in brackets. Both materials are specifically designed to fall within the natural lead isotopic variation and to assist users with the validation and verification of their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM-EB400), the other does not (ERM-AE142). As additional information, δ208/206PbNIST SRM981 values are provided for both materials. For ERM-AE142, a delta value of δ208/206PbNIST SRM981 = -28.21(30) ‰ was obtained, and for ERM-EB400, a delta value of δ208/206PbNIST SRM981 = -129.47(38) ‰ was obtained, with the associated expanded uncertainties (k = 2) given in brackets. KW - Lead isotope variations KW - Radiogenic isotopes KW - Isotope reference material KW - Metrology in chemistry KW - Measurement uncertainty PY - 2019 DO - https://doi.org/10.1111/ggr.12253 SN - 1751-908X SN - 1639-4488 VL - 43 IS - 1 SP - 23 EP - 37 PB - John Wiley & Sons AN - OPUS4-47383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Szymoniak, Paulina A1 - Kang, N.-J. A1 - Wang, D-Y A1 - Wurm, A. A1 - Schick, C. A1 - Schönhals, Andreas T1 - Influence of interfaces on the crystallization behavior and the rigid amorphous phase of poly(l-lactide)-based nanocomposites with different layered doubled hydroxides as nanofiller N2 - Based on the three-phase model of semi-crystalline polymers, we determined all phase fractions of the NiAl-LDH/PLLA nanocomposites in dependence on the concentration of the nanofiller. Moreover, the rigid amorphous fraction (RAF) was separated into the RAFcrystal and the RAFfiller unbiasedly. A detailed comparison to the related nanocomposite system MgAl-LDH/PLLA was made considering that Mg and Ni have different atomic weights. As a first result is was found that NiAl-LDH/PLLA displays a higher crystallization rate compared to MgAl-LDH/PLLA, which is related to the different morphologies of the two nanocomposite systems. For both systems RAFcrystal increases with increasing concentration of the nanofiller. This means in the case of the nanocomposite not each crystal produces the same amount of RAF, as often assumed. Also, RAFfiller increases with the concentration for both systems but in a different way. This is discussed considering again the different morphologies of both nanocomposites. KW - Polymer-based nanocomposites KW - Temperature modulated differential scanning calorimetry PY - 2019 DO - https://doi.org/10.1016/j.polymer.2019.121929 VL - 184 SP - 121929 PB - Elesevier Ltd. AN - OPUS4-49557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Purohit, Purv A1 - Huacuja Sánchez, Jesús A1 - Wang, D.-Y. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Heinrich, G. A1 - Schönhals, Andreas T1 - Structure - property relationships of nanocomposites based on polypropylene and layered double hydroxides N2 - Nanocomposites based on polypropylene (PP) and organically modified ZnAl layered double hydroxides (ZnAl-LDH) were prepared by melt blending and investigated by a combination of differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SAXS and WAXS), and dielectric relaxation spectroscopy (DRS). An average number of stack size of LDH layers is calculated by analyzing the SAXS data which is close to that of pure organically modified ZnAl-LDH. Scanning microfocus SAXS investigations show that the ZnAl-LDH is homogeneously distributed in the PP matrix as stacks of 4–5 layers with an intercalated morphology. DSC and WAXS results show that the degree of crystallinity decreases linearly with the increasing content of LDH. The extrapolation of this dependence to zero estimates a limiting concentration of ca. 40% LDH where the crystallization of PP is completely suppressed by the nanofiller. The dielectric spectra of the nanocomposites show several relaxation processes which are discussed in detail. The intensity of the dynamic glass transition (β-relaxation) increases with the concentration of LDH. This is attributed to the increasing concentration of the exchanged anion dodecylbenzenesulfonate (SDBS) which is adsorbed at the LDH layers. Therefore, a detailed analysis of the β-relaxation provides information about the structure and the molecular dynamics in the interfacial region between the LDH layers and the polypropylene matrix which is otherwise dielectrically invisible (low dipole moment). As a main result, it is found that the glass transition temperature in this interfacial region is by 30 K lower than that of pure polypropylene. This is accompanied by a drastic change of the fragility parameter deduced from the relaxation map. KW - Nanocomposites KW - Layered double hydroxide KW - Dielectric spectroscopy KW - X-ray scattering KW - Polypropylene PY - 2011 DO - https://doi.org/10.1021/ma200323k SN - 0024-9297 SN - 1520-5835 VL - 44 IS - 11 SP - 4342 EP - 4354 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Purohit, Purv A1 - Wang, D.-Y. A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Heinrich, G. A1 - Schönhals, Andreas T1 - Arrangement of layered double hydroxide in a polyethylene matrix studied by a combination of complementary methods N2 - Organically modified ZnAl Layered Double Hydroxides (ZnAl-LDH) was synthesized and melt blended with polyethylene to obtain nanocomposites. The resulting morphology was investigated by a combination of Differential Scanning Calorimetry (DSC), Small and Wide-angle X-ray scattering (SAXS and WAXS) and dielectric relaxation spectroscopy (DRS). The arrangement (intercalation) of polyethylene chains between LDH stacks was investigated employing SAXS. The homogeneity of the nanocomposites and average number of stack size (4–6 layers) were determined using scanning microfocus SAXS (BESSY II). DSC and WAXS results show that the degree of crystallinity decreases linearly with the increasing content of LDH. The extrapolation of this dependence to zero estimates a limiting concentration of ca. 45% LDH where the crystallization of PE is completely suppressed by the nanofiller. The dielectric spectra of the nanocomposites show several relaxation processes which are discussed in detail. The intensity of the dynamic glass transition (β-relaxation) increases with the concentration of LDH. This is attributed to the increasing concentration of the exchanged anion sodium dodecylbenzene sulfonate (SDBS) which is adsorbed at the LDH layers. Therefore, a detailed analysis of the β-relaxation provides information about the structure and the molecular dynamics in the interfacial region between the LDH layers and the polyethylene matrix which is otherwise dielectrically invisible (low dipole moment). KW - Dielectric spectroscopy KW - Polyethylene nanocomposites KW - Layered double hydroxides PY - 2012 DO - https://doi.org/10.1016/j.polymer.2012.03.041 SN - 0032-3861 SN - 1873-2291 VL - 53 IS - 11 SP - 2245 EP - 2254 PB - Springer CY - Berlin AN - OPUS4-25810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Purohit, Purv A1 - Kang, N. A1 - Wang, D.-Y. A1 - Falkenhagen, Jana A1 - Emmerling, Franziska A1 - Thünemann, Andreas A1 - Schönhals, Andreas T1 - Structure-property relationships of nanocomposites based on polylactide and MgAl layered double hydroxides N2 - Nanocomposites based on poly(ʟ-lactide) (PLA) and organically modified MgAl Layered Double Hydroxides (MgAl-LDH) were prepared by melt blending and investigated by a combination of Differential Scanning Calorimetry (DSC), Small- and Wide-Angle X-ray Scattering (SAXS, WAXS), and dielectric spectroscopy (BDS). Scanning microfocus SAXS investigations show that the MgAl-LDH is homogeneously distributed in the matrix as stacks of 6 layers and/or partly exfoliated layers. DSC and WAXS show that the degree of crystallinity decreases linearly with the content of LDH. The extrapolation of the dependencies (DSC and WAXS) to zero estimates a limiting concentration of LDH CCri of ca. 21 wt% where the crystallization of PLA is completely suppressed by the nanofiller. The dielectric behavior of neat PLA show two relaxation regions, a β-relaxation at low temperatures related to localized fluctuations and the α-relaxation at higher temperatures due to the dynamic glass transition. The dielectric spectra of the nanocomposites show several additional relaxation processes compared to neat PLA which are discussed in detail. For the nanocomposites around 260 K (ƒ = 1 kHz) an additional process is observed which intensity increases with increasing concentration of LDH. This process is mainly attributed to the exchanged dodecylbenzene sulfonate (SDBS) molecules which are adsorbed at the LDH layers and form a mixed phase with the polymer close to the layers and stacks. An analysis of this process provides information about the molecular dynamics in the interfacial region between the LDH layers and the PLA matrix which reveal glassy dynamics in this region. In the temperature range around 310 K (ƒ = 1 kHz) a further process is observed. Its relaxation rate has an unusual saddle-like temperature dependence. It was assigned to rotational fluctuations of water molecules in a nanoporous environment provided by the LDH filler. Above the glass transition temperature a further process is observed at temperatures above. It is related to Maxwell/Wagner/Sillars polarization due to the blocking of charges at the nanofiller. KW - Polymer based nanocomposites KW - Polylactide KW - Layered double hydroxides KW - Dielectric spectroscopy PY - 2015 DO - https://doi.org/10.1016/j.eurpolymj.2015.05.008 SN - 0014-3057 SN - 1873-1945 VL - 68 SP - 338 EP - 354 PB - Elsevier CY - Oxford AN - OPUS4-33257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -