TY - JOUR A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Jäger, Christian T1 - 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel-zeolite composites N2 - The influence of starting materials and synthesis route on the properties and the structure of cementitious sodium aluminosilicate gels is not fully understood, partly due their amorphous nature and the fact that they often contain residual reactants, which can make the results of single-pulse NMR spectroscopy applied to these materials difficult to interpret or ambiguous. To overcome some of these limitations, 29Si{27Al} TRAPDOR NMR as well as 27Al{29Si} and 27Al{1H} REDOR NMR spectroscopy were applied to materials synthesized by the one-part alkali-activation route from three different amorphous silica starting materials, including rice husk ash. The latter led to formation of a fully amorphous sodium aluminosilicate gel (geopolymer), while the materials produced from the other silicas contained amorphous phase and crystalline zeolites. Application of the double-resonance NMR methods allowed to identify hydrous alumina gel domains in the rice husk ash-based material as well as significantly differing amounts of residual silica in the three cured materials. Four-coordinated Al existed not only in the aluminosilicate gel framework but also in a water-rich chemical environment with only a small amount of Si in proximity, likely in the alumina gel or possibly present as extra-framework Al in the aluminosilicate gel. The results demonstrate how the employment of different silica starting materials determines the phase assemblage of one-part alkali-activated materials, which in turn influences their engineering properties such as the resistance against chemically/biologically aggressive media. KW - Alkali-activated materials KW - Solid-state NMR KW - Aluminium hydroxide KW - Rice husk ash PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469353 DO - https://doi.org/10.1039/C8RA09246J SN - 2046-2069 VL - 8 IS - 70 SP - 40164 EP - 40171 PB - Royal Society of Chemistry AN - OPUS4-46935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simoes, R. A1 - Bernades, C. A1 - Joseph, A. A1 - Piedade, F. A1 - Kraus, Werner A1 - Emmerling, Franziska A1 - Diogo, H. A1 - da Piedade, M. T1 - Polymorphism in simvastatin: Twinning, disorder, and enantiotropic phase transitions N2 - : Simvastatin is one of the most widely used active pharmaceutical ingredients for the treatment of hyperlipidemias. Because the compound is employed as a solid in drug formulations, particular attention should be given to the characterization of different polymorphs, their stability domains, and the nature of the phase transitions that relate them. In this work, the phase transitions delimiting the stability domains of three previously reported simvastatin forms were investigated from structural, energetics, and dynamical points of view based on single crystal X-ray diffraction (SCXRD), hot stage microscopy (HSM), and differential scanning calorimetry (DSC) experiments (conventional scans and heat capacity measurements), complemented with molecular dynamics (MD) simulations. Previous assignments of the crystal forms were confirmed by SCXRD: forms I and II were found to be orthorhombic (P212121, Z′/Z = 1/4) and form III was monoclinic (P21, Z′/Z = 2/4). The obtained results further indicated that (i) the transitions between different forms are observed at 235.9 ± 0.1 K (form III → form II) and at 275.2 ± 0.2 K (form II → form I) in DSC runs carried out at 10 K min−1 and close to these values when other types of techniques are used (e.g., HSM). (ii) They are enantiotropic (i.e., there is a transition temperature relating the two phases before fusion at which the stability order is reversed), fast, reversible, with very little hysteresis between heating and cooling modes, and occur under single crystal to single crystal conditions. (iii) A nucleation and growth mechanism seems to be followed since HSM experiments on single crystals evidenced the propagation of an interface, accompanied by a change of birefringence and crystal contraction or expansion (more subtle in the case of form III → form II), when the phase transitions are triggered. (iv) Consistent with the reversible and small hysteresis nature of the phase transitions, the SCXRD results indicated that the molecular packing is very similar in all forms and the main structural differences are associated with conformational changes of the “ester tail”. (v) The MD simulations further suggested that the tail is essentially “frozen” in two conformations below the III → II transition temperature, becomes progressively less hindered throughout the stability domain of form II, and acquires a large conformational freedom above the II → I transition. Finally, the fact that these transitions were found to be fast and reversible suggests that polymorphism is unlikely to be a problem for pharmaceutical formulations employing crystalline simvastatin because, if present, the III and II forms will readily convert to form I at ambient temperature. KW - Polymorphism KW - Twinning KW - Disorder KW - Simvastatine PY - 2018 DO - https://doi.org/10.1021/acs.molpharmaceut.8b00818 SN - 1543-8384 SN - 1543-8392 VL - 15 IS - 11 SP - 5349 EP - 5360 PB - American Chemical Society CY - Washington, DC AN - OPUS4-46927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Broadband dielectric spectroscopy to study soft matter systems N2 - The basics of broadband dielectric spectroscopy were introduced in detail. The analysis of the data was discussed. As application of broadband dielectric spectroscopy the alpha-relaxation (dynamic glass transition) and the chain dynamics of polymers were ilustrated. Further the application of dielectric spectroscopy to polymerbased nanocomposites and high preformance polymers was discussed in detail. T2 - Kolloquiumsvotrag am Karlsruher Instiut of Technology CY - Karlsruhe, Germany DA - 05.12.2018 KW - Broadband dielectric spectroscopy PY - 2018 AN - OPUS4-46910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Breitfeld, Steffen A1 - Scholz, Gudrun A1 - Emmerling, Franziska A1 - Kemnitz, Erhard T1 - BaF-Coordination polymers: Mechanochemical syntheses of new coordination polymers with a direct Ba-F bond N2 - Metal organic frameworks (MOFs) and coordination polymers (CPs) Play an important role in different fields of applications like e.g. catalysis, separations, gas storages, sensors or optoelectronics. Moreover, particularly fluorinated metal-organic frameworks (FMOFs) are in the focus of interest during the last years. Due to the strong electronegativity of fluorine the FMOFs show beside an enhanced thermal stability excellent optical and electrical properties compared to non-fluorinated frameworks. In most cases fluorine is implemented using perfluorinated organic linkers at the synthesis, usually performed by solvothermal synthesis. However, only few examples are known so far where fluorine is coordinated directly to the metal cation. Recently we reported about successful mechanochemical syntheses and characterization of fluorine-containing coordination polymers of alkaline earth metals by milling M(OH)2 (M: Ca, Sr, Ba) with fluorinated benzene dicarboxylic acids. In the present study, it was shown that it is possible to connect fluorine directly to Barium using a mechanochemical synthesis route. A new phase pure barium coordination polymer, BaF-benzene-dicarboxylate (BaF(p-BDC)0.5), was synthesized by milling starting either from barium hydroxide or from barium acetate as sources for barium cations. In both cases the second reactant was 1,4-benzenedicarboxylic acid (H2(p-BDC)). Ammonium fluoride was used as fluorinating agent directly at milling. Although single crystals are not accessible so far and the structure was not solved yet, both the 19F MAS NMR spectrum and the FT IR spectrum give strong evidence that fluorine as well as 1,4-benzenedicarboxylate are connected to barium. This is the first mechanochemical synthesis of coordination polymers where fluorine is directly coordinated to the metal cation. The new compound BaF(p-BDC)0.5 was characterized by X-ray powder diffraction, FT IR- and 19F, 1H-13C CP MAS NMR spectroscopies, DTA-TG and elemental analysis. T2 - Konferenz CY - Oberjoch, Germany DA - 22.07.20108 KW - Mechanochemical syntheses KW - Coordination polymers KW - Direct fluorine-metal bond KW - Alkaline earth metal PY - 2018 AN - OPUS4-46897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Tumanov, N. A1 - Tumanova, N. A1 - Fischer, Franziska A1 - Morelle, F. A1 - Ban, V. A1 - Robeyns, K. A1 - Filinchuk, Y. A1 - Wouters, J. A1 - Leyssens, T. T1 - Exploring polymorphism and stoichiometric diversity in naproxen/proline cocrystals N2 - We present naproxen/proline cocrystals discovered when combining enantiopure and racemic naproxen and proline. Using liquid-assisted grinding as the main method to explore the variety of crystal forms in this system, we found 17 cocrystals, of which the structures of only four of them were previously known. The naproxen/proline system exhibited multiple polymorphs of 1 : 1 stoichiometry as well as more rare cocrystals with 1 : 2 and 2 : 3 stoichiometries, two cocrystal hydrates and one cocrystal solvate. In situ ballmilling, used to monitor liquid-assisted grinding reactions, revealed that the solvent dictates the reaction intermediates even if the final reaction product stays the same. Synchrotron X-ray diffraction data collected in situ upon heating allowed us to monitor directly the phase changes upon heating and gave access to pure diffraction patterns of several cocrystals, thus enabling their structure determination from powder X-ray diffraction data; this method also confirmed the formation of a conglomerate in the RS-naproxen/DL-proline system. Proline in cocrystals kept its ability to form charge-assisted head-to-tail N-H⋯O hydrogen bonds, typical of pure crystalline amino acids, thus increasing the percentage of strong chargeassisted interactions in the structure and consequently providing some of the cocrystals with higher melting points as compared to pure naproxen. The majority of drugs are chiral, and hence, these data are of importance to the pharmaceutical industry as they provide insight into the challenges of chiral cocrystallization. KW - In situ KW - Mechanochemistry KW - XRD PY - 2018 UR - https://pubs.rsc.org/en/Content/ArticleLanding/CE/2018/C8CE01338A#!divAbstract DO - https://doi.org/10.1039/c8ce01338a SN - 1466-8033 VL - 20 IS - 45 SP - 7308 EP - 7321 PB - Royal Society of Chemistry CY - London AN - OPUS4-46913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chapartegui, Ander A1 - Emmerling, Franziska A1 - Schneider, Rudolf T1 - MOFs as optical sensor elements against endocrine disrupting phthalates N2 - The development of optical sensing technologies for Endocrine Disrupting Chemicals (EDCs) was urgently needed to facilitate currently unmet demands on comprehensive monitoring of These substances, thus ensuring consumer safety. T2 - SALSA CY - Berlin, Germany DA - 01.05.2018 KW - MOF KW - Short chained phthalates PY - 2018 AN - OPUS4-46889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chapartegui, Ander A1 - Emmerling, Franziska A1 - Schneider, Rudolf T1 - Metal-Organic Frameworks as turn on fluorescent optical sensors against endocrine disrupting phthalate plasticizers N2 - The development of quick and simple optical sensing technologies for Endocrine Disrupting Chemicals (EDCs) is needed to facilitate monitoring of these substances to ensure consumer safety. Optical sensing was achieved against phthalates acting as EDC that have host guest interaction with an intercalated Metal-organic framework (MOF), resulting in a fluorescence emission upon excitation. The fluorescent turn-on signal was generated by using a fluorophore with a structural component that has little fluorescence unless excimers are formed. Strategies to engineer functional MOF structures suitable for sensing EDC phthalates were developed, and the characterization of the MOFs with and without present phthalates was done by single crystal XRD, PXRD, RAMAN and Thermogravimetry. Extensive photo-physical characterization of host-guest complexes of different phthalates and the MOF as well as the resulting exciplex fluorescence was performed. Photo physical characterization revealed an analyte specific fluorescence fingerprint that allows discerning even minute changes in chemical structures of the analyte and therefore paving the way for sensing tools in real world analytical applications. The presented capability of MOFs to sense EDCs is envisioned to complement established methods from analytical chemistry such as mass spectrometry based methods which can’t be used on site and are often associated with infrastructural capacity constraints T2 - EURoptrode CY - Naples, Italy DA - 25.03.2018 KW - MOF KW - Short chained Phthalates PY - 2018 AN - OPUS4-46890 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded A1 - Böllinghaus, Thomas T1 - BAM’s role in materials science and hydrogen in metals: TOF-SIMS imaging N2 - Due to its low mass and high diffusivity in presence of compositional, thermal and mechanical gradients, hydrogen within a metallic microstructure can result in severe loss in ductility even at low concentrations and might lead eventually to a catastrophic and unpredictable failure of structural components during service. In this context, hydrogen mapping at the microscale is still considered among the most important challenges on the pathway towards a better understanding of the hydrogen transport and assisted cracking phenomena in metals, specifically in structural components, e.g. steels. Among the very few available techniques to localize hydrogen at the microscale, Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a reliable tool. Based on the assumption that deuterium influence the microstructure similarly to hydrogen, in the following contribution ToF-SIMS was applied as the main technique to detect and locally map the deuterium distribution in several alloys: lean 2101 and standard 2205 duplex stainless steel (DSS), AISI 304L austenitic stainless steel and titanium 6Al-4V alloy. These alloys were selected as case studies in this work due to the wide use of them in many applications and environments which frequently provide critical conditions for hydrogen absorption and assisted degradation. The innovative design of in-situ and ex-situ experiments enabled us to elucidate the permeation, transport and trapping of deuterium in the microstructure in sub-micron resolution for the first time. In addition to the novel experimental setups, further progress was gained by applying computational multivariate data analysis (MVA) on the raw data and data fusion with high resolution structural characterization methods (scanning electron microscopy and electron back-scattered diffraction – SEM/EBSD). This combination allowed us to correlate the deuterium distribution and the influence on the microstructure. T2 - 4th Symposium on Innovative Measurement and Analysis for Structural Materials CY - Tokyo, Japan DA - 13.11.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - Austenitic stainless steel KW - Principal Component Analysis KW - Data-fusion PY - 2018 UR - https://unit.aist.go.jp/tia-co/project/SIP-IMASM/sympo/2018/index.html AN - OPUS4-46867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Hydrogen assisted cracking phenomena in duplex stainless steels elucidated by in- and ex-situ ToF-SIMS experiments N2 - In the presented research, the high potential and abilities of secondary ion mass spectrometry (ToF-SIMS) to detect and locally map the hydrogen distribution in two types of duplex stainless steels are shown. The research validates certain proposed mechanisms by combining ToF-SIMS with high-resolution scanning electron microscopy and electron-backscattered diffraction. The combination of data from several techniques on the same region was conducted in this field for the first time by applying data treatment of the ToF-SIMS raw data and data fusion approach. This powerful combination of methods allows reviewing of the occurring processes related to hydrogen assisted cracking. The step beyond the state of the art in this field was gained here by developing permeation and mechanical loading experiments within the ToF-SIMS during chemometric imaging of the hydrogen distribution in the microstructure. The research presents the necessary correlation between the hydrogen distribution and the resulted structural changes, the diffusion behavior in a duplex microstructure and stress induced diffusion of hydrogen by applying external load at the microscale. T2 - 6th WMRIF Early Career Scientist Summit CY - NPL Teddington UK DA - 18.06.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - LDX KW - EBSD KW - Data-fusion PY - 2018 AN - OPUS4-46865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Sekundärstrahlungsemission bei der UKP-Laser-Anwendung: Herausforderung für die Arbeitssicherheit N2 - Im Vortrag werden die Risiken, insbesondere die unerwünschte Erzeugung von Röntgenstrahlung, bei der Nutzung ultrakurzer Laserimpulse in der Materialbearbeitung beschrieben. Neue Anforderungen an den Arbeitsschutz werden dargestellt. T2 - SPECTARIS, Deutscher Industrieverband für optische, medizinische und mechatronische Technologien e.V., Veranstaltung Technische Kommission Photonik CY - Berlin, Germany DA - 27.11.2018 KW - Ultrakurze Laserimpulse KW - Materialbearbeitung KW - Röntgenstrahlung KW - Arbeitsschutz PY - 2018 AN - OPUS4-46859 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -