TY - CONF A1 - Markötter, Henning T1 - Hard X-Ray Imaging Capabilities at BAMline (BESSY II) N2 - The BAMline at the 3rd generation synchrotron X-ray source BESSY II has been supporting researchers in a wide range of research areas for over 20 years. In addition to materials science, these fields also include biology, cultural heritage, and medicine. Being a non-destructive characterization method, synchrotron X-ray imaging, in particular tomography (SXCT), plays a particularly important role in structural characterization. A recent upgrade of key BAMline equipment expands the imaging capabilities: The upgraded dual multilayer monochromator offers flexibility by providing different energy spectra to optimize flux and energy resolution as desired. Different spectra (8 – 60 keV with ΔE/E 0.01%, 1.5%, 4% and pink beam) can be selected. The upgraded detector (in white beam configuration, equipped with an sCMOS camera) allows the higher flux to be exploited with reduced readout times. Shorter tomographic acquisition times in the range of seconds are now possible. Hence, in-situ and operando examinations are routinely available. An integrated slip ring allows continuous rotation of the sample stage for ease of wiring. The pink beam option allows tomographic observation of processes occurring in the time domain of a few seconds with a resolution down to ~ 1 µm. Different scan methods, optimized for quality and speed are available and discussed. Examples of energy related materials from fuel cell and battery research are shown. An optional end station allows refraction enhanced imaging (synchrotron X-Ray refraction radiography (SXRR) and tomography (SXRCT)). That includes an analyzer Si-crystal in Bragg alignment between sample and detector. This technique obtains sensitivity to smaller structures (cracks, pores) down to a few wavelengths, while obtaining field of view sizes in the range of several mm. Besides medicine (e.g., teeth explants), several applications are found in material science, like studies on diesel particulate filters, ceramics, additively manufactured (AM) alloys and metal matrix composites (MMC). The in-situ capabilities include mechanical load (tension and compression) and heating up to 1100°C. A case study, the microstructural evolution during heat treatment of an AM AlSi10Mg, will be shown. T2 - 15th International Conference on X-Ray Microscopy (XRM 2022) CY - Online meeting DA - 19.06.2022 KW - BAMline KW - X-ray imaging KW - Tomography PY - 2022 AN - OPUS4-55691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Explaining deviatoric residual stresses and load transfer in aluminum alloys and composites with complex microstructure N2 - The residual stresses and load transfer in multiphase metal alloys and their composites (with both random planar-oriented short fibers and particles) will be shown, as studied by neutron diffraction, by X-ray computed tomography, and by a model based on the reformulation of classic Maxwell’s homogenization method. Contrary to common understanding and state-of-the-art models, we experimentally observe that randomly oriented phases possess non-hydrostatic residual stress. Moreover, we disclose that the unreinforced matrix alloy stays under hydrostatic compression even under external uniaxial compression. The recently developed modeling approach allows calculating the residual stress in all phases of the composites. It rationalizes the presence of deviatoric stresses accounting for the interaction of random oriented phases with fibers having preferential orientation. It also allows the explanation of the unconventional in-situ behavior of the unreinforced alloy and the prediction of the micromechanical behavior of other similar alloys. T2 - MLZ Conference 2022: Neutrons for Mobility CY - Lenggries, Germany DA - 31.05.2022 KW - Load transfer KW - Neutron Diffraction KW - micromechanical modeling KW - Computed tomography PY - 2022 AN - OPUS4-55405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - Tomographic Imaging Capabilities with hard X-Rays at BAMline (Bessy II) N2 - The BAMline at the synchrotron X-ray source BESSY II (Berlin, Germany) is supporting researchers in a wide range of research areas since more than 20 years. These fields include biology, cultural heritage, medicine, and also materials science. As a non-destructive characterization method, synchrotron X-ray imaging, especially tomography with hard X-Rays, plays an important role in structural 3D characterization. A recent upgrade of key equipment at the BAMline expands the imaging capabilities towards shorter acquisition times. Therefore, in-situ and operando experiments can now be routinely conducted. Also, different energy resolutions can be set up to optimize flux and energy resolution as desired. This requires an adaptation of the used reconstruction methods in order to perform necessary analyses also during the experiment. In this presentation the equipment, data handling pipeline as well as various examples from material science are presented. T2 - 5th Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities (SNI 2022) CY - Berlin, Germany DA - 05.09.2022 KW - BAMline KW - X-ray imaging KW - Tomography PY - 2022 AN - OPUS4-55692 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Procedures to Quantitatively Characterize Morphological Features of Triply Periodic Minimal Surface Structures (TPMSS) N2 - The residual stresses and load transfer in multiphase metal alloys and their composites (with both random planar-oriented short fibers and particles) will be shown, as studied by neutron diffraction, by X-ray computed tomography, and by a model based on the reformulation of classic Maxwell’s homogenization method. Contrary to common understanding and state-of-the-art models, we experimentally observe that randomly oriented phases possess non-hydrostatic residual stress. Moreover, we disclose that the unreinforced matrix alloy stays under hydrostatic compression even under external uniaxial compression. The recently developed modeling approach allows calculating the residual stress in all phases of the composites. It rationalizes the presence of deviatoric stresses accounting for the interaction of random oriented phases with fibers having preferential orientation. It also allows the explanation of the unconventional in-situ behavior of the unreinforced alloy and the prediction of the micromechanical behavior of other similar alloys. T2 - 5th International Conference on Tomography of Materials and Structures CY - Grenoble, France DA - 27.06.2022 KW - Load transfer KW - Neutron Diffraction KW - Micromechanical modeling KW - Computed tomography PY - 2022 AN - OPUS4-55406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - Synchrotron X-Ray Tomography Techniques at BAMline N2 - A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and operando studies can now be routinely performed, and different energy spectra can easily be set up. In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired. T2 - HZB User Meeting CY - Online meeting DA - 08.12.2022 KW - BAMline KW - X-ray imaging KW - Tomography PY - 2022 AN - OPUS4-56568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - The combined use of X-ray refraction and trans-mission radiography and computed tomography N2 - Alternative to conventional transmission-based radiography and computed tomography, X-ray refraction techniques are being increasingly used to detect damage in light materials. In fact, their range of application has been recently extended even to metals. The big advantage of X-ray refraction techniques is that they are able to detect nanometric defects, whose size would lie below the resolution of even state-of-the-art synchrotron-based X-ray computed tomography (SXCT). The superiority of synchrotron X-ray refraction radiography and tomography (SXRR and SXRCT) has been shown in the case of light materials, in particular composites. X-ray refraction techniques also yield a quantitifaction of the amount of damage (the so-called relative internal specific surface) and can well be compared with damage models. At the same time, it is impossible for SXRR and SXRCT to image single defects. We show that the combination of refraction- and transmission-based imaging techniques yields an impressive amount of additional information about the type and amount of defects in microstructured materials such as additively manufactured metals or metal matrix composites. We also show that the use of data fusion techniques allows the classification of defects in statistically significant representative volume elements. T2 - 11th Conference on Industrial Computed Tomography CY - Online meeting DA - 08.02.2022 KW - X-ray refraction radiography KW - Computed Tomography KW - Synchrotron radiation KW - Additive manufacturing KW - Damage evolution PY - 2022 AN - OPUS4-54327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chemello, Giovanni T1 - Characterization of Graphene using HAXPES N2 - Since its discovery, graphene has got growing attention in the industrial and application research due to its unique properties . However, graphene has not been yet implemented into the industrial market, in particularly due to the difficulty of properly characterizing this challenging material. As most of other nanomaterials, graphene’s properties are closely linked to its chemical and structural properties, such as number of layers, flake thickness, degree of functionalisation and C/O ratio. For the commercialization, suitable procedures for the measurement and characterization of the ultrathin flakes, of lateral dimensions in the range from µm to tens of µm, are essential.Surface chemical methods, especially XPS, have an outstanding role of providing chemical information on the composition. Thereby, one well-known problem for surface analytical methods is the influence of contamination on the composition as in the case of adventitious carbon. The differentiation between carbon originated from the contamination or from the graphene sample itself is often not obvious, which can lead to altered results in the determination of the composition. To overcome this problem, Hard Energy X-ray Photoelectron Spectroscopy (HAXPES) offers new possibilities due to its higher information depth. Therefore, XPS measurement obtained with Al Kα radiation (E = 1486. 6 eV) were compared with analyses performed with a Cr Kα (E = 5414. 8 eV) excitation on functionalized graphene samples. Differences are discussed in terms of potential carbon contamination, but also of oxygen on the composition of the samples. Measurements are performed on O-, N- and F-functionalized graphene. Different preparation procedures (powder, pellet, drop cast from liquid suspension) will be also discussed, correlation of the results with the flakes morphology as well as their validation with other independent methods are in progress. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Graphene KW - Functionalized graphene KW - Depth profiling PY - 2022 AN - OPUS4-56814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - XPS of GR2M N2 - The activities of ISO-G-Scope are presented. The influence of the sample preparation and the results of XPS/HAXPES measurements are discussed. T2 - Graphene Workshop @ ISO TC 229 Meeting CY - Teddington, UK DA - 16.11.2022 KW - Graphene related materials KW - X-ray photoelectron spectroscopy KW - Sample preparation KW - Hard X-ray photoelectron spectroscopy PY - 2022 AN - OPUS4-56434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions N2 - In the face of rising energy demand and the impending climate change the development of a sustainable, fossil-free fuel and chemical production is of global importance. One possible goal is the development of electrochemical conversion processes using catalysts. Porous materials play an important role in such energy applications. The activity and stability of each catalyst is highly dependent on the properties of the coating, i.e., phase composition, crystallinity, accessible surface area, and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physico-chemical properties. However, the complex morphology of such catalysts constitutes a challenge even for modern analytical techniques. Spectroscopic ellipsometry (SE) is a versatile method for studying material properties by using appropriate models (e.g., film thickness, optical and electronic properties). Ellipsometric models need to be validated in order to produce accurate results. In a first step, the model for the ellipsometric fit studies of a calcination series of mesoporous iridium oxide films (300 – 600 °C) was investigated and validated with respect to their material properties.[4] The information on electronic structure of the catalysts shows a direct correlation with electrochemical activities. The development of an environmental electrochemical cell offers the possibility of investigations under operando conditions. Thus, changes in optical and electronic properties can be induced and monitored during the electrocatalytic oxygen evolution reaction. T2 - 9th International Conference on Spectroscopic Ellipsometry CY - Beijing, China DA - 22.05.2022 KW - Mesoporous iridium oxide films KW - Non-destructive operando analysis KW - Oxygen evolution reaction KW - Spectroscopic ellipsometry PY - 2022 AN - OPUS4-54915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Procop, Mathias A1 - Terborg, R. T1 - Measurement and calculation of x-ray production efficiencies for copper, zirconium, and tungsten N2 - Electron probe microanalysis (EPMA) is based on physical relations between measured X-ray intensities of characteristic lines and their Xray production efficiency, which depends on the specimen composition. The quality of the analysis results relies on how realistically the physical relations describe the generation and emission of X-rays. Special experiments are necessary to measure X-ray production efficiencies. A challenge in these experiments is the determination of the detection efficiency of the spectrometer as a function of the photon energy. An energy-dispersive spectrometer was used in this work, for which the efficiency was determined at metrological synchrotron beamlines with an accuracy of ±2%. X-ray production efficiencies for the L series and the Kα series of copper and zirconium and for the M and L series of tungsten were determined at energies up to 30 keV in a scanning electron microscope. These experimental values were compared with calculated X-ray production efficiencies using physical relations and material constants applied in EPMA. The objective of the comparison is the further improvement of EPMA algorithms as well as extending the available database for X-ray production efficiencies. Experimental data for the X-ray production efficiency are also useful for the assessment of spectrum simulation software. KW - Copper KW - Electron probe microanalysis KW - Tungsten KW - X-ray production efficiency KW - Zirconium PY - 2022 DO - https://doi.org/10.1017/S1431927622012351 VL - 28 IS - 6 SP - 1865 EP - 1877 PB - Oxford University Press CY - Oxford AN - OPUS4-55711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Kai T1 - ToF-SIMS as a new tool for nano-scale investigation of ps-laser generated surface structures on Titanium substrates N2 - The fabrication of laser-generated surface structures on titanium and titanium alloys has recently gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces. The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, the effective number of laser pulses per beam spot area, etc. A simple way to characterize laser-generated surface structures is by means of optical microscopy (OM) or white light interference microscopy (WLIM). The latter can address the surface topography, while having a lateral resolution limit of ~(lambda)/2 (lambda = illumination wavelength). To resolve morphologies with spatial periods significantly smaller than (lambda)/2, scanning electron microscopy (SEM) is often used, taking benefit of the reduced de Broglie wavelength associated to the electrons of several keV energy. However, all the above-mentioned techniques lack the necessary depth-resolution to reveal and quantify sub-surface material modifications of these laser-generated structures. Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) represents a promising surface analytical technique for studying laser-induced chemical surface alterations since the method combines a high surface sensitivity with the capability to perform a depth-profiling of the laser-affected surface zone. In this study we combine WLIM and high-resolution SEM with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti-6Al-4V alloys upon irradiation by near infrared ultrashort laser pulses (1030 nm, 925 fs) at different laser fluence levels, effective number of pulses, and at different pulse repetition rates (1 – 400 kHz). We show how this combined surface analytical approach allows to evaluate alterations in the surface chemistry and topography of the laser-generated surface structures depending on the laser processing parameters T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Laser-induced periodic surface structures KW - Time of Flight - Secondary ion mass spectrometry KW - White light interferometric microscopy KW - Titanium alloy PY - 2022 AN - OPUS4-54992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - van Wasen, S. A1 - You, Yi A1 - Beck, S. A1 - Riedel, Jens A1 - Volmer, D. A. T1 - Laser Ablation Secondary Electrospray Ionization for In Situ Mass Spectrometric Interrogation of Acoustically-Levitated Droplets N2 - The composition of acoustically levitated droplets was probed by a novel combination of mid-IR laser evaporation and subsequent postionization via secondary electrospray ionization. The combination of microliter samples and subnanoliter sampling provided time-resolved interrogation of droplets and allowed for a kinetic investigation of the laser-induced release of the analyte, which was found to strongly depend on the analytes. The observed substancespecific delayed release of the analytes permitted baseline-separated discrimination of the analytes, ideal for the study of complex samples. The additionally applied postionization scheme was found to enable efficient detection of small volatile compounds as well as peptides. The detection of small molecules and peptides occurred under very different sampling geometries, pointing to two distinct underlying ionization mechanisms. Overall, our results suggest that the experimental setup presented in this study can serve as a widely applicable platform to study chemical reactions in acoustically levitated droplets as model reactors. KW - Acoustic levitation KW - Mass spectrometry KW - Electrospray KW - Laser ablation PY - 2022 DO - https://doi.org/10.1021/acs.analchem.2c03800 SN - 0003-2700 VL - 2022 SP - 1 EP - 5 PB - ACS Publications CY - Washington AN - OPUS4-56531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishurova, Tatiana T1 - In-situ imaging of additively manufactured alloys at the BAMline N2 - In this work, we present the recent in-situ imaging developments at the BAMline (of synchrotron BESSY II, HZB), focused on the in-situ characterization and understanding of microstructural evolution of additively manufactured materials subjected to different environments. Two show cases are presented. In the first, X-ray refraction radiography (SXRR) was combined with in-situ heat treatment to monitor the microstructural evolution as a function of temperature in a laser powder bed fusion (LPBF) manufactured AlSi10Mg alloy. We show that SXRR allows detecting the changes in the Si-phase morphology upon heating using statistically relevant volumes. SXRR also allows observing the growth of pores (i.e., thermally induced porosity), usually studied via X-ray computed tomography (XCT), but using much smaller fields-of-view. In the second case study, XCT was combined with in-situ tensile test to investigate the damage mechanism in a LPBF Aluminum Metal Matrix Composite (MMC). In-situ SXCT test disclosed the critical role of the defects in the failure mechanism along with pre-cracks in the reinforcement phase of MMC. We found that cracks were initiated from lack-of-fusion defects and propagated through coalescence with other defects. T2 - New Frontiers in Materials Design for Laser Additive Manufacturing CY - Montabaur, Germany DA - 22.05.22 KW - Additive manufacturing KW - Laser powder bed fusion KW - Synchrotron X-ray computed tomography KW - Synchrotron X-ray Refraction PY - 2022 AN - OPUS4-54900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishurova, Tatiana A1 - Evsevleev, Sergei A1 - Mehta, B. A1 - Nyborg, L. A1 - Virtanen, E. A1 - Markötter, Henning A1 - Hryha, E. A1 - Bruno, Giovanni T1 - Failure Mechanisms Investigation by Means of in-situ Synchrotron Computed Tomography in Aluminum MMC-based Alloy Tailored for Additive Manufacturing (AM) N2 - The availability of high-performance Al alloys in AM is limited due to difficulties in printability, requiring both the development of synergetic material and AM process to mitigate problems such as solidification cracking during laser powder bed fusion (LPBF). The goal of this work was to investigate the failure mechanism in a LPBF 7017 Aluminium alloy + 3 wt% Zr + 0.5 wt% TiC. The processing leads to different categories of Zr-rich inclusions, precipitates and defects. T2 - Alloys for Additive Manufacturing Symposium 2022 (AAMS22) CY - Munich, Germany DA - 11.09.2022 KW - Additive manufacturing KW - Laser powder bed fusion KW - Synchrotron X-ray computed tomography KW - MMC PY - 2022 AN - OPUS4-56110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Reliable, and reproducible physico-chemical data of nanomaterials for risk assessment N2 - Nanoforms with at least one dimension below 100 nm have an important part to play in more and more areas of our daily life. Therefore, risk assessment of these materials is becoming increasingly important. In this context, the European Chemical Agency (ECHA) considered eleven physico-chemical properties as relevant, of which the following six are essential for the registration: chemical composition, crystallinity, particle size, particle shape, surface chemistry and specific surface area. Four of these priority properties can be obtained with electron microscopy and surface analytics like XPS and ToF-SIMS. The reliability of this data must be ensured, especially for their use for grouping and read across approaches. On the other hand, the “reproducibility” crisis has revealed major shortcomings in the reliability of published data. In a case study, we show how the quality of the data can be ensured by using existing standards and protocols of each step in the workflow of sample characterization. As exemplary samples, two Al-coated TiO2 samples as nanopowders were selected from the JRC repository, capped either with a hydrophilic or a hydrophobic organic ultrathin shell. SEM results provided the size and shape of the nanoparticles, a first overview about the composition was obtained with EDS. XPS and ToF-SIMS supplied the surface chemistry, especially information about the shell and the coating of the particles. Standards and protocols of all steps of the analytical workflow including preparation and data reduction are discussed regarding reliable and reproducible data. Additionally, uncertainties for the different steps are specified. Only such a detailed description of all these factors allows a comprehensive physico-chemical characterization of the nanoparticles with understanding of their potential risk assessment. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Reference data KW - Risk assessment KW - Nanomaterials KW - Titania PY - 2022 AN - OPUS4-54961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - VAMAS ILC of functionalized Graphene by XPS and Graphene Oxide by SEM N2 - The ideas of the planned VAMAS interlaboratory comparisons of functionalized graphene and graphene oxide are presented. T2 - Stakeholder Advisory Board ISO-G-Scope CY - Online meeting DA - 12.01.2022 KW - Graphene KW - XPS KW - SEM PY - 2022 AN - OPUS4-54375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Ines A1 - Al-Sabbagh, Dominik A1 - Bentrup, U. A1 - Marquardt, Julien A1 - Schmid, Thomas A1 - Scoppola, E. A1 - Kraus, Werner A1 - Stawski, Tomasz A1 - de Oliveira Guilherme Buzanich, Ana A1 - Yusenko, Kirill A1 - Weidner, Steffen A1 - Emmerling, Franziska T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure. KW - Bismuth KW - In situ EXAFS KW - In situ SAXS/WAXS KW - Lacunary Keggin ion KW - Polyoxometalates KW - Self-assembly PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823 DO - https://doi.org/10.1002/chem.202200079 SN - 0947-6539 VL - 28 IS - 27 SP - 1 EP - 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pollard, M. T1 - Functionalized Poly(ethylene glycol)s (PEGs) as a Reference Material for Detection of Polymeric end Groups via SEC Hyphenated with FTIR and 1H-NMR (80 MHz) N2 - With the online coupling (or hyphenation) of chemically-resolved spectroscopy detection with classical size-exclusion chromatography (SEC) it is possible to correlate polymer molecular size with chemical structure in a single in-situ or on-flow measurement. Medium-resolution 1H-NMR (60 MHz) spectroscopy (i.e., “desktop NMR”) and Fouriertransform Infrared Spectroscopy (FTIR) have both been developed as coupled methods (SEC-MR-NMR, SEC-FTIR) for the detection of polymer analytes by monitoring e.g. alkene or carbonyl functionality.1,2 Here, we have investigated the potential for the detection of polymer end groups, using a slightly higher field-strength spectrometer (80 MHz 1H Larmor frequency) and taking advantage of a columnless injection method that provides bulk spectra for reference. End-functionalized polymers were synthesized by reaction of PEG with toluene isocyanate, yielding ,-functionalized polymers with exactly 2 IR- and NMR-detectable functional groups per chain, as proven by MALD-TOF mass spectrometry. We have investigated the sensitivity (limit of detection) and spectral resolution for these functional groups in chloroform, THF, and water. Results have demonstrated a good feasibility for the simultaneous online detection of PEG backbone (M~4000 g/mol) and these end groups at the level of ca. 2 mol%. T2 - 33rd International Symposium on Chromatography CY - Budapest DA - 18.09.2022 KW - Size exclusion chromatography KW - Polyethyleneglycol KW - MALDI-TOF MS KW - NMR PY - 2022 AN - OPUS4-56716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization N2 - Coupling of chromatographic and spectrometric techniques for polymer characterization; focus topics: LCxMALDI-TOF-MS and UPLC x ESI-TOF-MS T2 - 16. Tagung des Arbeitskreises Polymeranalytik CY - Online meeting DA - 22.03.2022 KW - Liquid chromatography KW - Mass spectrometry KW - Polymers KW - Two-dimensional chromatography (2D-LC) PY - 2022 AN - OPUS4-54567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heilmann, Maria T1 - Size-Tunable Ni-Cu Core-Shell Nanoparticles: Structure, Composition, and Catalytic Activity N2 - Nanoparticles (NPs) have become important materials for a variety of chemical technologies, including catalysis. One of the main challenges is the reduction of green house gases, such as CO2. One opportunity besides the capturing is the conversion to synthesis gas via the reverse water-gas shift reaction. A facile and efficient method is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core-shell NPs. The diameter of the NPs can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio from 30:1 to 1:1. The NPs are structurally characterized with combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. Using these analytical methods, a core-shell-shell structure their chemical composition is elucidated. A depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core-shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction). T2 - Nanoalloys: recent developments and future perspectives Faraday Discussion CY - London, UK DA - 21.09.2022 KW - Nanoparticles KW - Core-shell KW - Catalysis PY - 2022 AN - OPUS4-56831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -