TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Schönauer-Kamin, D. A1 - Moos, R. A1 - Giovanelli, F. A1 - Rabe, Torsten T1 - Influence of pressure assisted sintering and reaction sintering on microstructure and thermoelectric properties of bi-doped and undoped calcium cobaltite N2 - Calcium cobaltite (Ca3Co4O9) is considered as one of the most promising thermoelectric p-type oxides for energy harvesting applications at temperatures above 500 °C. It is challenging to sinter this material as its stability is limited to 920 °C. To facilitate a practicable and scalable production of Ca3Co4O9 for multilayer generators, a systematic study of the influence of powder calcination, Bi-doping, reaction sintering, and pressure-assisted sintering (PAS) on microstructure and thermoelectric properties is presented. Batches of doped, undoped, calcined, and not calcined powders were prepared, tape-cast, and sintered with and without uniaxial pressure at 900 °C. The resulting phase compositions, microstructures and thermoelectric properties were analysed. It is shown that the beneficial effect of Bi-doping observed on pressureless sintered samples cannot be transferred to PAS. Liquid phase formation induces distortions and abnormal grain growth. Although the Seebeck coefficient is increased to 139 µV/K by Bi-doping, the power factor is low due to poor electrical conductivity. The best results were achieved by PAS of calcined powder. The dense and textured microstructure exhibits a high power factor of 326 µW/mK² at 800 °C but adversely high thermal conductivity in the relevant direction. The figure of merit is higher than 0.08 at 700 °C. KW - Ceramics KW - Calcium cobaltite KW - Thermoelectric properties KW - Calcination KW - Pressure-assisted sintering PY - 2019 DO - https://doi.org/10.1063/1.5107476 SN - 0021-8979 VL - 126 IS - 7 SP - 075102-1 EP - 075102-11 PB - AIP Publishing CY - Melville AN - OPUS4-48708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Gawek, Marcel A1 - Madkour, S. A1 - Schönhals, Andreas T1 - Confinement and localization effects revealed for thin films of the miscible blend Poly(vinyl methyl ether) / Polystyrene with a composition of 25/75 wt% N2 - Thin films (200-7nm) of the asymmetric polymer blend poly(vinyl methyl ether) (PVME)/polystyrene (PS) (25/75wt%) were investigated by broadband dielectric spectroscopy (BDS). Thicker samples ([Formula: see text]37 nm) were measured by crossed electrode capacitors (CEC), where the film is capped between Al-electrodes. For thinner films ([Formula: see text]37 nm) nanostructured capacitors (NSC) were employed, allowing one free surface in the film. The dielectric spectra of the thick films showed three relaxation processes ( [Formula: see text] -, [Formula: see text] - and [Formula: see text] -relaxation), like the bulk, related to PVME fluctuations in local spatial regions with different PS concentrations. The thickness dependence of the [Formula: see text] -process for films measured by CECs proved a spatially heterogeneous structure across the film with a PS-adsorption at the Al-electrodes. On the contrary, for the films measured by NSCs a PVME segregation at the free surface was found, resulting in faster dynamics, compared to the CECs. Moreover, for the thinnest films ([Formula: see text]26 nm) an additional relaxation process was detected. It was assigned to restricted fluctuations of PVME segments within the loosely bounded part of the adsorbed layer, proving that for NSCs a PVME enrichment takes place also at the polymer/substrate interface. KW - Thin polymer films KW - Broadband dielectric spectroscopy PY - 2019 DO - https://doi.org/10.1140/epje/i2019-11870-3 SN - 1292-895X VL - 42 IS - 8 SP - 101, 1 EP - 11 PB - Springer AN - OPUS4-48651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - B, Yang A1 - Chua, Y. Z. A1 - Szymoniak, Paulina A1 - Carta, M A1 - Malpass-Evans, R A1 - McKeown, N A1 - Harrison, W A1 - Budd, P A1 - Schick, C A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Effect of backbone rigidity on the glass transition of polymers of in-trinsic microporosity probed by fast scanning calorimetry N2 - Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships including physical aging. In this context the glass transi-tion plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs be-fore their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs. KW - Polymers of intrinsic microporosity KW - Fast scanning calormetry PY - 2019 DO - https://doi.org/10.1021/acsmacrolett.9b00482 SN - 2161-1653 VL - 8 IS - 8 SP - 1022 EP - 1028 PB - ACS Publications AN - OPUS4-48617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Rigid amorphous phase in polymer nanocomposites as revealed by dielectric relaxation spectroscopy and fast scanning calorimetry N2 - For inorganic/polymer nanocomposites a so-called Rigid Amorphous Phase (RAF) is formed in the interfacial region by adsorption of polymer segments onto the nanoparticles. The segmental dynamics of RAF is expected to be altered, as compared to the pure matrix, which might percolate into the entire system, affecting the overall nanocomposite properties. A combination of two relaxation spectroscopy techniques (Broadband Dielectric Spectroscopy (BDS) and Specific Heat Spectroscopy (SHS) in a form of Temperature Modulated DSC (TMDSC)) as well as Fast Scanning Calorimetry (FSC) was employed to investigate the structure and molecular mobility of nanocomposites based on Epoxy and Layered Doubled Hydroxides with different nanoparticle content. First, BDS investigations proved the existence of a process, which is present only for nanocomposites, assigned to the dynamics of polymer segments within RAF. Second, the amount of RAF was quantified by analyzing the change of specific heat capacity step of nanocomposites, comparing to the pure material. Thirdly, the glass transition of nanocomposites was studied with FSC, applying high heating rates (500-10 000 K/s). Considering that all techniques probe essentially the same molecular process, an activation plot was constructed, delivering a complete picture of the molecular mobility and structure of the polymer nanocomposites including RAF. T2 - American Physical Society (APS) March Meeting 2019 CY - Boston, MA, USA DA - 04.03.2019 KW - Nanocomposites KW - Rigid amorphous fraction PY - 2019 AN - OPUS4-47564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Rigid Amorphous Phase in Epoxy-based Nanocomposites as Revealed by Dielectric Spectroscopy and Fast Scanning Calorimetry N2 - For inorganic/polymer nanocomposites a so-called Rigid Amorphous Phase (RAF) is formed in the interfacial region by adsorption of polymer segments onto the nanoparticles. The segmental dynamics of RAF is expected to be altered, as compared to the pure matrix, which might percolate to the entire system, affecting the overall nanocomposite properties. A combination of two relaxation spectroscopy techniques (Broadband Dielectric Spectroscopy (BDS) and Temperature Modulated DSC (TMDSC)) as well as Fast Scanning Calorimetry (FSC) was employed to investigate the structure and molecular mobility of nanocomposites based on Epoxy and Layered Doubled Hydroxides with different nanoparticle content. First, BDS investigations proved the existence of a process, which is present only for nanocomposites, assigned to the dynamics of polymer segments within RAF. Second, the amount of RAF was quantified by analyzing the change of specific heat capacity step of nanocomposites, comparing to the pure material. Thirdly, the glass transition of nanocomposites was studied with FSC, applying high heating rates (0.5-10 kK/s). Considering that all techniques probe essentially the same molecular process, an activation plot was constructed, delivering a complete picture of the molecular mobility and structure of the polymer nanocomposites including RAF. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 01.04.2019 KW - Rigid amorphous fraction KW - Nanocomposites PY - 2019 AN - OPUS4-47762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Madkour, Sherif T1 - Multiple Glassy Dynamics of an Asymmetric PVME/PS Blend Investigated by Broadband Dielectric and Specific Heat Spectroscopy N2 - Over the past decades research on the molecular dynamics of miscible polymer blends is of topical interest in the literature, to understand the segmental mobility of individual components, as it is affected by blending. In general, miscible polymer blends exhibit a complex dynamic behavior. For an A/B blend the relaxation times of component A and component B are affected by the spatial local compositional heterogeneity, present in binary systems on a microscopic level, regardless of the macroscopic homogeneity. Here, a combination of broadband dielectric and specific heat spectroscopy was employed to study the dynamically asymmetric PVME/PS blend with seven different compositions, focusing on samples with high PS contents. Considering that PS is dielectrically invisible, BDS is a powerful technique to study the response of PVME, as it is affected by PS segments. Here, three separate relaxation processes were found by dielectric investigations, related to confined or constrained PVME segments due to the spatial local compositional heterogeneities, which is in contrary to the previous literature findings [1]. Moreover, the dielectric data was compared with results obtained by specific heat spectroscopy, where a fourth relaxation process was found, due to the cooperative fluctuations of PVME and PS. [1] Colmenero, J., Arbe, A. Soft Matter, 2007, 3, 1474. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 01.04.2019 KW - Specific heat spectroscopy KW - Polymer blends KW - Dielectric spectroscopy PY - 2019 AN - OPUS4-47764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Wörterbuch der Metallurgie und Metallverarbeitung ‐ Englisch‐Deutsch – Deutsch‐Englisch N2 - Die erste Auflage dieses klassischen Wörterbuches enthält hochspezialisierte Fachbegriffe nicht nur aus dem Bereich der Metallurgie, sondern auch zum Schweißen, Löten und zur Korrosion. Besonderer Wert wurde vom Autor auf einen korrekten Bezug zum jeweiligen Anwendungsgebiet gelegt. Letztendlich erfüllt das Wörterbuch das Ansinnen seines Autors,aus der Vielzahl von Quellen und Anwendungsgebieten die relevanten Begriffe mit dem korrekten Pendant zusammenzustellen und bietet dem Nutzer eine Grundlage für korrekte Begrifflichkeit und Kommunikation im internationalen Kontakt. KW - Metallurgie PY - 2019 DO - https://doi.org/10.1002 maco.201970096 SN - 1521-4176 SN - 0947-5117 VL - 70 IS - 9 SP - 4 EP - 5 PB - WILEY‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48888 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munasir, A1 - Triwikantoro, A1 - Zainuri, M. A1 - Bäßler, Ralph A1 - Darminto, T1 - Corrosion Polarization Behavior of Al-SiO2 Composites in 1M NaCl and Related Microstructural Analysis N2 - The composites combining aluminum and silica nanoparticles with the addition of tetramethylammonium hydroxide (Al-SiO2(T)) and butanol (Al-SiO2(B)) as mixing media have been successfully fabricated. Corrosion behavior of Al-SiO2 composites before and after exposure in 1M NaCl solution was examined using potentiodynamic polarization (Tafel curve analysis). The study was also equipped with scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) investigations. Before exposure, Al-SiO2(T) exhibited the best corrosion resistance. Performance improvement was indicated by Al-SiO2(B) up to 10 times better than Al-SiO2(T) after exposure. The increased SiO2 content did not significantly enhance the corrosion resistance of the composites. The Al-SiO2 composites with 5% SiO2 content showed very high corrosion resistance (as the optimum composition). Furthermore, pitting corrosion was observed in the Al-SiO2 composites, indicated by the formation of corrosion products at grain boundaries. The product was affected by the presence of SiO2 in the Al matrix and the NaCl environment at 90 °C (approach to synthetic geothermal media: Na+, Cl, H+, OH-). Our study revealed the presence of γ-Al2O3, γ-Al(OH)3, and Al(OH)2Cl as the dominant corrosion products. KW - Al-Composite KW - Corrosion KW - Corrosion rate KW - SiO2 Nanoparticle KW - Tafel Plot PY - 2019 DO - https://doi.org/10.5829/ije.2019.32.07a.11 SN - 1025-2495 SN - 1735-9244 VL - 7 IS - 32 SP - 982 EP - 990 PB - Materials and Energy Research Center AN - OPUS4-48742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Effect of CO2 gas on carbon steel corrosion in an acidic-saline based geothermal fluid N2 - Geothermal energy is one of the most promising energy resources to replace fossil fuel. To extract this energy, hot fluids of various salts and gases are pumped up from a geothermal well having a certain depth and location. Geothermal wells in volcanic regions often contain highly corrosive CO2 and H2S gases that can be corrosive to the geothermal power-plants, which are commonly constructed of different steels, such as carbon steel. This research focuses on the corrosion behaviour of carbon steel exposed to an artificial geothermal fluid containing CO2 gas, using an artificial acidic-saline geothermal brine as found in Sibayak, Indonesia. This medium has a pH of 4 and a chloride content of 1,500 mg/L. Exposure tests were conducted for seven days at 70 °C and 150 °C to simulate the operating temperatures for low and medium enthalpy geothermal sources. Surface morphology and cross-section of the specimens from the above experiments were analysed using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Electrochemical tests via open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were performed to understand the corrosion processes of carbon steel in CO2-containing solution both at 70 °C and 150 °C. Localized corrosion was observed to a greater extent at 70 °C due to the less protectiveness of corrosion product layer compared to that at 150 °C, where FeCO3 has a high corrosion resistance. However, a longer exposure test for 28 days revealed the occurrence of localized corrosion with deeper pits compared to the seven-day exposed carbon steel. In addition, corrosion product transformation was observed after 28 days, indicating that more Ca2+ cations incorporate into the FeCO3 structure. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Carbon steel KW - CO2 KW - EIS KW - Geothermal KW - Corrosion PY - 2019 SP - Paper 200245, 1 EP - 5 CY - Madrid, Spain AN - OPUS4-49099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Conjugated polymers: Perspective, theory, and new materials (Book review) N2 - In this also completely rewritten and reorganized second part of the two‐volume set 45 international experts comprise the current knowledge of conjugated polymers. In addition to part one on properties, processing characterization and morphology, 16 chapters cover perspectives, theory and new materials. Finally, it can be concluded that this 4th edition of this handbook fulfills, like the first part, its intention, to be the definitive resource on the topic of conducting polymers. This is assured by the updated and added contributions of all authors, which consider the significant developments both in fundamental understanding, progress and applications since publication of the previous edition. So, it can be recommended to everyone, who wants to get a comprehensive overview on conjugated polymers, not just to researchers, advanced students, and industry professionals working in materials science and engineering. KW - Polymer KW - Testing PY - 2019 DO - https://doi.org/10.1002/maco.201970094 SN - 1521-4176 SN - 0947-5117 VL - 70 IS - 9 SP - 1727 PB - WILEY‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Verschleiß metallischer Werkstoffe ‐ Erscheinungsformen sicher beurteilen N2 - Das in der 3. Auflage vorliegende Fachbuch wird die praktische Arbeit des Ingenieurs bei der Beurteilung von Verschleißerscheinungen unterstützen. In acht Kapiteln behandeln die Autoren alle interessanten Aspekte zu diesem Thema. Zielgruppen sind Maschinen-bauingenieure, Techniker und Werkstofftechniker in der Entwicklung, Konstruktion und Instandhaltung. Sie werden für ihre Arbeit im Buch gute Unterstützung und Anregungen für ihre praktische Arbeitfinden. KW - Verschleiß PY - 2019 DO - https://doi.org/10.1002/maco.201970096 SN - 1521-4176 SN - 0947-5117 VL - 70 IS - 9 SP - 4 EP - 4 PB - WILEY‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48887 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pötzsch, Sina T1 - Practical Testing and Evaluation of Plastics (Book review) N2 - One can conclude, this first edition of “Practical Testing and Evaluation of Plastics” provides a comprehensive and compact reference. It can be recommended as clear overview as well as introducing manual for everyone working with characterization and testing of plastics. KW - Plastic KW - Testing PY - 2019 DO - https://doi.org/10.1002maco.201970054 SN - 0947-5117 SN - 1521-4176 VL - 70 IS - 05 SP - 931 EP - 932 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Ghasem Zadeh Khorasani, Media A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Water as side effect of reinforcing boehmite filler Local changes in anhydride cured epoxy resin N2 - Nanocomposites offer wide opportunities for lightweight constructions and enable reduction of weight and volume. Beside macroscopic toughening nanoparticle reinforced polymers show a soft interface around boehmite (AlOOH) filler nanoparticles. A related strong interaction between boehmite and the anhydride cured resin system is widely suspected in literature but not determined by structural Analysis. Determination of the molecular structure is important to allow simulations approaching the real system and predict future reinforcing effects. DRIFT (diffuse refletance infrared fourier transformed) spectra of the boehmite reinforced anhydride cured epoxy show significant changes in the molecular structure compared to the neat polymer. Further investigations of the interactions between the single components of the resin system and the boehmite filler pointed out reactions between released water released from the boehmite filler and the anhydride hardener or amine accelerator. This leads to the discussion of competing polymerisation mechanisms that highly influence the polymer properties. Ongoing experiments and literature research approve that this impact of water is able to locally change the stoichiometrie, alter the curing mechanism or support an inhomogeneous crosslink density. T2 - Polydays 2019 CY - Erwin-Schrödinger-Zentrum, Berlin Adlershof, Germany DA - 11.09.2019 KW - Nanocomposites KW - Epoxy KW - FTIR spectroscopy KW - Boehmite alumina PY - 2019 AN - OPUS4-49010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Ghasem Zadeh Khorasani, Media A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - New Focus On Boehmite-Reinforced Nanocomposites Molecular Approach With Advanced FTIR-Techniques N2 - By FTIR-study it was possible to proof a chemical reaction between boehmite and the hardener of anhydride cured epoxy resins. Future studies can assume that the chemical environment of the resin system is changed in the surrounding of boehmite nanoparticles. This highly affects especially localized properties. T2 - 6th International Conference on Multifunctional, Hybrid and Nanomaterials CY - Sitges, Spain DA - 11.03.2019 KW - Nanocomposite KW - Boehmite KW - FTIR KW - DRIFTS KW - Epoxy PY - 2019 AN - OPUS4-47785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Evaluation of a multi-purpose measurement cell for standardized volume resistivity measurements at high temperatures N2 - The ProboStat is a multi-purpose measurement cell suitable for various electrical and physical measurements under different atmospheres and at high temperatures. Disc and bar shaped samples are sandwiched between platinum electrodes at the top of the tubular cell. The gas tight assembly can be inserted into a furnace. Different gases can be flushed through the tube. For this study, a ProboStat was adapted to measure volume resistivity of ceramic insulators at high temperatures according to standards. The standardized measurement of volume resistivity of ceramic insulators requires the consideration of many specifications including sample diameter, thickness, electrode design, and the proportion of these characteristics. Measurements are ideally performed in a state of dielectric equilibrium. The time-related slope of resistivity of a specific sample follows a power function. Thus, care must be taken when choosing a charge time or defining the duration of a measurement. As fringing of the guarded electrode occurs under high voltage, the effective electrode area for evaluation of the results should be corrected with respect to sample thickness and electrode design. The demands of effective standards on sample geometry and electrode design are stricter for room temperature measurements than for high temperature measurements. To perform high temperature measurements on ceramic samples that also fulfill the demands on room temperature measurements, a ProboStat was equipped with a dedicated large sample setup for discs with diameters of up to 60 mm. The volume resistivity of different alumina samples was first measured at room temperature in a standard test fixture and then compared to results obtained with the ProboStat. All measurements were performed for at least 100 min using a 26 mm guarded electrode. High temperature measurements at 500 °C were performed using the same samples. Room temperature values obtained with the standard test fixture are in the order of 10^17 Ohm·cm. The quantitative effect of electrode area correction is presented. Practical issues related to the use of the multi-purpose cell are addressed. These include electrode material selection, application of electrodes, and compensation of leakage currents. High temperature results of volume resistivity of the different alumina samples are presented. The validity is discussed with respect to the suitability of the multi-purpose cell for such measurements. T2 - XVI Conference and Exhibition of the European Ceramic Society (ECerS 2019) CY - Torino, Italy DA - 16.06.2019 KW - ceramics KW - alumina KW - volume resistivity PY - 2019 AN - OPUS4-48270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - View into the Depths of Copolymer Microstructure N2 - For different kinds of polymers it will be shown how it could be realized to obtain information on small, sometimes isomeric topological heterogeneities by coupling UPLC / ESI-TOF-MS and LC /MALDI-TOF-MS. T2 - DSM, Fall Meeting CY - Breda, The Netherlands DA - 07.11.2019 KW - Microstructure KW - LC-MS KW - Copolymer PY - 2019 AN - OPUS4-49587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. G. A1 - Agudo Jácome, Leonardo T1 - Thermodynamic study of a refractory complex concentrated alloy (rCCA) using the CALPHAD method N2 - Multi-principal-element alloys (MPEAs), have recently come to the attention of the scientific community due to their potential for improving properties such as, e.g. mechanical strength and oxidation resistance in high temperature structural applications. The AlMo0.5NbTa0.5TiZr refractory (r)CCA is one such candidate, showing a two-phase microstructure after a two-stage heat treatment under argon atmosphere at a controlled cooling rate. Since the application conditions intended for this alloy require a long-term high temperature (> 700 °C) mechanical and oxidation resistance, it becomes necessary to assess the possible phase development in this regime. The diagrams reveal that two BCC-based phases could form during alloy solidification, where one phase would be enriched with Mo, Nb and Ta while the other phase, with Al, Ti and Zr. Activity oxides diagrams show that a stable form of aluminum oxide (α-Al2O3, Pearson symbol: hR10, corundum) can be formed. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - Chemically Complex Alloy KW - CALPHAD KW - Electromicroscopy PY - 2019 AN - OPUS4-50730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - View into the depths of copolymer microstructure by a special approach of LC-MS data evaluation N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. This is and will remain a challenge for analysts. First a very short overview will be given concerning the common liquid separation techniques for polymers (SEC, LAC, LCCC, GELC) coupled to soft ionization mass spectrometric methods like MALDI and ESI-MS with focus on their limitations. For very broadly distributed samples or chemical very similar species the superposition of different separation mechanisms in chromatography is unavoidable or the separation efficiency cannot be optimized. Different ionization probabilities and species of the same nominal mass with completely different structures are just two problems of mass spec of complex polymer mixtures. Subsequently, different examples will be shown how these limitations in some cases could be outsmarted. First example will be the separation of statistical EO-PO copolymers of different chemical compositions by end group functionality and the quantification of end group fractions over the whole CCD. Here an UP-LCCC / ESI-TOF-MS coupling is applied. Further for different kinds of polymers it will be shown how it could be realized to obtain information on small isobaric/isomeric topological heterogeneities by coupling UP-SEC / ESI-TOF-MS. All results are based on the data processing of reconstructed ion chromatograms of single mass traces of complex ESI-MS spectra. T2 - SCM-9 CY - Amsterdam, The Netherlands DA - 29.01.2019 KW - Reconstructed ion chromatograms KW - Copolymer KW - Microstructure KW - LC x ESI-TOF-MS PY - 2019 AN - OPUS4-47836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geyler, Paul A1 - Rabe, Torsten A1 - Mieller, Björn A1 - Léonard, Fabien T1 - Machine learning assisted evaluation of the shape of VIAs in a LTCC multilayer N2 - The introduction of the 5G technology and automotive radar applications moving into higher frequency ranges trigger further miniaturization of LTCC technology (low temperature co-fired ceramics). To assess dimensional tolerances of inner metal structures of an industrially produced LTCC multilayer, computer tomography (CT) scans were evaluated by machine learning segmentation. The tested multilayer consists of several layers of a glass ceramic substrate with low resistance silver-based vertical interconnect access (VIA). The VIAs are punched into the LTCC green tape and then filled with silver-based pastes before stacking and sintering. These geometries must abide by strict tolerance requirements to ensure the high frequency properties. This poster presents a method to extract shape and size specific data from these VIAs. For this purpose, 4 measurements, each containing 3 to 4 samples, were segmented using the trainable WEKA segmentation, a non-commercial machine learning tool. The dimensional stability of the VIA can be evaluated regarding the edge-displacement as well as the cross-sectional area. Deviation from the ideal tubular shape is best measured by aspect ratio of each individual layer. The herein described method allows for a fast and semi-automatic analysis of considerable amount of structural data. This data can then be quantified by shape descriptors to illustrate 3-dimensional information in a concise manner. Inter alia, a 45 % periodical change of cross-sectional area is demonstrated. T2 - DKG Jahrestagung 2019 CY - Leoben, Austria DA - 06.05.2019 KW - Machine Learning KW - LTCC multilayer KW - 5G PY - 2019 AN - OPUS4-48289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dudziak, Mateusz A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Thermal properties of polymer nanocomposites based on polycarbonate (PC) and boehmite N2 - Nanocomposites are extremely versatile due to their physicochemical properties, which differ significantly from bulk homopolymers. One of the inorganic nanomaterials which are increasingly used as a filler in polymer matrices is boehmite, typically used as an inexpensive flame retardant. Here, it is used as a nanofiller in polycarbonate and polyamide, expecting to improve their mechanical properties. For industrial use boehmite is obtained by the solvothermal method, resulting in a layered nanomaterial, whereas naturally it occurs as single crystals with the size of <100µm. In this work we are obtaining and isolating boehmite crystals by a bottom-up method, in which a reaction between aluminum nitride and sodium hydroxide. Obtaining boehmite as microcrystals is necessary for its analysis and characterization, as well as to investigate its interaction with polymer matrices at the polymer/particle interface. Here, the obtained particles in polymer matrices are characterized with differential scanning calorimetry and thermogravimetry analysis. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 31.03.2019 KW - Boehmite KW - Polycarbonate PY - 2019 AN - OPUS4-47768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Falkenhagen, Jana A1 - Becker, Roland A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tschiche, Harald A1 - Reinsch, Stefan A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Analytical toolset to characterize polyurethanes after exposure to artificial weathering under systematically varied moisture conditions N2 - Polyether and -ester urethanes (PU) were exposed to artificial weathering at 40 °C and artificial UV radiation in a weathering chamber. In 3 parallel exposures, humidity was varied between dry, humid, and wet conditions. Material alteration was investigated by various analytical techniques like size exclusion chromatography (SEC), liquid chromatography-infrared spectroscopy (LC-FTIR), thermal-desorption gas chromatography-mass spectrometry (TD-GC-MS), fluorescence mapping and dynamic mechanical analysis (DMA). Our results show that depending on the weathering conditions, different degradation effects can be observed. By means of SEC an initial strong decrease of the molar masses and a broadening of the mass distributions was found. After a material dependent time span this was followed by a plateau where molar mass changes were less significant. A minor moisture-dependent degradation effect was only found for polyester PU. Fluorescence measurements on two materials revealed an increase in the luminescence intensity upon weathering process reaching a saturation level after about 500 h. The changes in the optical properties observed after different exposure conditions and times were very similar. The TD-GC-MS data showed the fate of the stabilizers and antioxidant in the course of weathering. LC-FTIR measurements revealed a change in peak intensities and the ratio of urethane and carbonyl bands. KW - Polyurethane KW - Artificial weathering KW - Moisture KW - Crosslinking KW - Degradation PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819303708 DO - https://doi.org/10.1016/j.polymertesting.2019.105996 SN - 0142-9418 VL - 78 SP - 105996, 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-48625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lin, Xuebao A1 - Tan, Yi A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Schoch, R. A1 - Lang, M. A1 - Schartel, Bernhard T1 - Weathering Resistance of Halogen-free Flame Retardance in E&E Polymeric Materials N2 - Nowadays, various polymeric materials are used in E&E applications with sufficient flame retardance by adding rather different flame retardants. It doesn’t matter whether cables are used outdoor or are installed indoor as building products, the weathering exposures such as UV radiation, humidity and variation in temperature occur and influence the flame-retardant property. Recently, the lifetime of the flame retardance itself becomes an increasingly important factor. In this work, several devices were used to perform accelerated artificial ageing simulating different environment exposures. The comprehensive and global understanding of the durability of flame retardance in dependence on the weathering or ageing conditions is still a matter of discussion. Therefore, the weathering resistance of various halogen-free fire-retarded polymers was investigated in this work. Polymeric systems with different kinds of fire retardants were chosen, including various fire retardant mechanisms. Ethylene Vinyl Acetate (EVA) blends with high amounts of inorganic flame retardant such as aluminum hydroxide (ATH), boehmite and synergists, which mainly dilutes the polymer resin work as heat sink and cooling agent, and enhance residue formation was examined. Thermoplastic Polyurethane (TPU) was modified with melamine cyanurate (MC), which mainly acts by changed melt flow and dripping behavior as well as fuel dilution. Additionally, aluminum diethylphosphinate and boehmite are induced as assistant flame retardant. Furthermore, glass fiber reinforced Polyamide 66 (PA) was investigated containing different kinds of aluminum diethylphosphinate based flame retardant mixtures, which acts by flame inhibition and additional char formation. The degradation of the surface was analyzed after the different weathering conditions. Most of the specimens exhibited an intensive material degradation at the top surface accompanied by a distinct discoloration, e.g. getting darker or showing yellowing. The weathering of the EVA samples lead to numerous cracks (already) after 4000 h. The corresponding changes in the chemical structure was investigated by ATR FT-IR for all materials. The flammability was investigated by cone calorimeter, UL-94 burning chamber, and oxygen index (LOI) using plate and bar specimens. The flame retardance of most of the materials studied degrades only slightly or were rather stable for the investigated exposure times. Interestingly, also some opposite results were found. EVA modified by different inorganic flame retardants such as ATH achieved higher LOI after exposing in the humidity chamber and the accelerated oxidation under water in the autoclaves. It is suggested that the particle size of ATH and boehmite plays an important role, when these flame retardants agglomerate at the surface during accelerated weathering. Both materials, EVA and TPU, were also investigated as cable jackets. While EVA modified with inorganic flame retardants exhibits low-smoke and non-dripping fire behavior, TPU flame-retarded with MC yields cables with pronounced melt-dripping. Cone calorimeter tests were carried out using cable rafts of the size of 100 mm * 100 mm as well as our self-made cable module test, which simulates the vertical full-scale test of a bundle of cables at the bench-scale. Both methods were used to investigate the weathering resistance of the flame retardance in cables. The results of the cable module test for the flame-retarded EVA cables were only slightly affected even when a long time hydrothermal ageing was carried out. This is because of inorganic residue which just delays the fire growth but does not extinguish. However, for the flame-retarded TPU cable jackets, the cable module test exhibited an accelerated fire spread and a melt-dripping behavior which was promoted by weathering exposure. T2 - FRPM 2019, 17th European Meeting on Fire Retardant Polymeric Materials CY - Turku, Finland DA - 26.06.2019 KW - Cable KW - Flame retardant KW - Weathering resistance KW - Durability KW - ethylene vinyl acetate KW - Thermoplastic polyurethane KW - Flammability PY - 2019 AN - OPUS4-48553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zirnstein, Benjamin A1 - Schulze, Dietmar A1 - Schartel, Bernhard T1 - The impact of polyaniline in phosphorus flame retardant ethylene-propylene-diene-rubber (EPDM) N2 - Usually elastomers are loaded with high amounts of flame retardants to fulfill fire safety requirements. In this study the potential char precursor polyaniline (PANI) and the established fire retardant pentaerythritol (PER) were implemented in ethylene-propylene-diene monomer rubber (EPDM). PANI and PER were used in low loadings (7 phr) and combined with two phosphorous flame retardants, Ammonium polyphosphate (APP) and a piperazine-pyrophosphate/phosphoric acid compound (FP), to boost their performance. A comprehensive study is presented, explaining the impact of PANI on curing and mechanical properties, including compensation for the plasticizer-like effect of APP in EPDM, and improved flame retardancy. In the cone calorimeter test, the combination of EPDM/FP/PANI reduced the effective heat of combustion by 20%. All nine EPDM rubber compounds were investigated with the LOI and UL 94 tests, cone calorimeter, FMVSS 302 and glow wire testing to quantify fire performance. The PANI containing EPDM rubbers, EPDM/APP/PANI and EPDM/FP/PANI outperformed the corresponding PER containing, EPDM/APP/PER and EPDM/FP/PER rubbers in various tests. Moreover, the study investigated the impact of PANI and PER on the mode of action of the phosphorus species and showed that the addition of PANI increased the amount of phosphorus in the condensed phase. To receive a broader understanding of the flame retardant mode of action of PANI in combination with APP and FP, calculations were carried out to estimate the impact of PANI on the protective layer effect. KW - EPDM KW - Rubber KW - Flame retardant KW - Polyaniline KW - Pentaerythritol PY - 2019 DO - https://doi.org/10.1016/j.tca.2019.01.019 SN - 0040-6031 VL - 673 SP - 92 EP - 104 PB - Elsevier B.V. AN - OPUS4-47503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Hertwig, Andreas A1 - Matjacic, L. A1 - McMahon, G. A1 - Kotil, L. A1 - Bernsmeier, D. A1 - Kraehnert, R. T1 - Analysis of elemental composition and porosity of mesoporous iridium titanium mixed oxide thin films for energy application by SEM/EDS N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with energy dispersive X-ray spectroscopy (EDS) at an SEM. T2 - Microscopy & Microanalysis 2019 Meeting CY - Portland, OR, USA DA - 04.08.2019 KW - Mesoporous mixed metal oxide films KW - SEM/EDS/STRATAGem KW - EPMA KW - Ellipsometry KW - NanoSIMS PY - 2019 AN - OPUS4-48767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Kotil, L. A1 - Hodoroaba, Vasile-Dan A1 - Bernsmeier, Denis A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Spectroscopic ellipsometric analysis of elemental composition and porosity of mesoporous iridium-titanium mixed oxide thin films for electrocatalytic splitting of water N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge for modern analytical techniques and requires approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by spectroscopic ellipsometry (SE). Mesoporous iridium oxide - titanium oxide (IrOx-TiOx) films were prepared via dip-coating of a solution containing a triblock-copolymer as structure-directing agent, an iridium precursor as well as a titanium precursor in ethanol. Deposited films with different amounts of iridium (0 wt%Ir to 100 wt%Ir) were synthesized and calcined in air. The thin films were analyzed with SE using the Bruggeman effective medium approximation (BEMA) for modelling. The results were compared with electron probe microanalysis (EPMA) as part of a combined SEM/EDS/STRATAGem Analysis. T2 - 8th International conference on spectroscopic ellipsometry (ICSE-8) CY - Barcelona, Spain DA - 26.05.2019 KW - Mesoporous iridium-titanium mixed oxides KW - Thin films KW - Spectroscopic ellipsometry KW - Oxygen evolution reaction KW - EPMA KW - Ellipsometric porosimetry PY - 2019 AN - OPUS4-48387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Hertwig, Andreas A1 - Kotil, L. A1 - Kraehnert, R. T1 - Analysis of elemental composition and porosity of mesoporous iridium titanium mixed oxide thin films for energy application by SEM/EDS N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with energy dispersive X-ray spectroscopy (EDS) at an SEM. KW - Electron probe microanalysis (EPMA) KW - Iridium-titanium mixed oxides KW - Spectroscopic ellipsometry KW - Mesoporous thin films KW - NanoSIMS PY - 2019 DO - https://doi.org/10.1017/S1431927619009589 SN - 1431-9276 (Print) SN - 1435-8115 (Online) VL - 25 IS - S2 (August) SP - 1770 EP - 1771 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-48768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Daniel A1 - Resch-Genger, Ute T1 - Development of reference materials (WP1) and reference methods (WP2) for the standardisation of concentration measurements of extracellular vesicles N2 - BAM provides leading expertise in preparation, characterisation and application of fluorescent reference standards and biomedical relevant nanomaterials, as well as in traceable, absolute, and quantitative fluorometric measurements of transparent and scattering systems in the ultraviolet, visible, and near infrared spectral region. BAM will prepare solid low-RI particles in WP1, will develop reference methods to determine the fluorescence intensity and RI of reference materials in WP2, and will measure the fluorescence intensity of EVs in biological test samples of WP3. T2 - EMPIR 18HLT01 "MetVesII" Kick-off meeting CY - Delft, The Netherlands DA - 17.06.2019 KW - Reference materials KW - Reference methods KW - Extracellualr vesicles PY - 2019 AN - OPUS4-48813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawek, Marcel A1 - Hertwig, Andreas A1 - Schönhals, Andreas T1 - Growth Kinetics and Molecular Mobility of Irreversibly Adsorbed Layers in Thin Polymer Films N2 - In well-annealed thin polymer films, with non-repulsive polymer/substrate interactions, an irreversibly adsorbed layer is formed. These adsorbed layers have shown enormous potential for technological applications. The growth kinetics and molecular dynamics of these buried layers in thin films are still not fully investigated due to the hard accessibility. Here, the irreversibly adsorbed layers of homopolymer thin films are revealed by solvent-leaching experiments. The growth kinetics of these layers is investigated as a function of original film thickness and annealing times. The thickness, topography and quality of the adsorbed layer is determined with Atomic Force Microscopy (AFM) and spectroscopic ellipsometry. Additionally, the molecular mobility of the adsorbed layer is investigated with Broadband Dielectric Spectroscopy (BDS). A recently developed nanostructured capacitor (NSC) is employed to measure the adsorbed layers with a free surface layer depending on annealing and solvent-leaching time. The results are quantitatively compared and discussed with respect to recently published work. T2 - Spring Meeting of German Physical Society CY - Regensburg, Germany DA - 31.03.2019 KW - Adsorbed layer KW - Thin polymeric films PY - 2019 AN - OPUS4-47767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hennersdorf, Felix A1 - Weltschev, Margit A1 - Hertwig, Andreas T1 - ATR Investigations into the effect of ageing on HD-PE heating oil storage tanks after a service life of more than 30 years N2 - Heating oil storage tanks made of polyethylene grades have been on the market in Germany since the early 1970s. To ensure safety, their replacement is recommended by tank manufacturers after a period of 30 years. Polyethylene is subject to ageing by alteration of the properties during its life cycle. The degree of degradation and the nature of the process mainly depend on the chemical alteration of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no data available on the long-term behaviour of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was to find a suitable test method to determine the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s. Therefore, tank sections from the bottom, the shell and the roof of 22 individual storage tanks produced of polyethylene grades A and B have been examined by Melt Flow Rate (MFR) and Attenuated Total Reflectance (ATR). Their service life was in the range between 20 and 41 years. The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). An increase of the MFR was determined for the samples of polyethylene grade A, whereas a reduction of the MFR values was measured for most samples of polyethylene grade B. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer. ATR analysis exhibits an absorption band at 909 cm‒1 predominantly in samples of polyethylene grade A indicating chain scission and concomitantly formed terminal vinyl groups. This absorption band can be used for the characterization of the ageing of the polyethylene grades. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Heating oil tanks KW - Polyethylene KW - Ageing KW - Service life PY - 2019 AN - OPUS4-49000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ermilova, Elena A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Schneider, S. A1 - Peters, S. T1 - Standardization of spectroscopic ellipsometry as GUM-compliant accredited measurement method N2 - Ellipsometry has become a powerful measurement tool in semiconductor industry since the sixties of the last century. Early standardization activities focused exclusively on SiO2/Si (ASTM F 576-01, SEMI 3624). The first generic standard dealing with ellipsometry is DIN 50989-1:2018 Ellipsometry – Part 1: Principles. Standardization is a prerequisite for accreditation according to DIN EN ISO/IEC 17025 and the evaluation of uncertainty budgets. T2 - 8th International conference on spectroscopic CY - Barcelona, Spain DA - 26.05.2019 KW - Standardization of Ellipsometry KW - GUM-compliance KW - Uncertainty budgets KW - Bulk material PY - 2019 AN - OPUS4-48348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Hertwig, Andreas A1 - Kraehnert, R. A1 - Hodoroaba, Vasile-Dan T1 - Analysis of elemental composition and porosity of mesoporous IrOx-TiOx thin films by SEM/EDS N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with energy dispersive X-ray spectroscopy (EDS) at an SEM. T2 - EMAS 2019 - 16th European Workshop on MODERN DEVELOPMENTS AND APPLICATIONS IN MICROBEAM ANALYSIS CY - Trondheim, Norway DA - 19.05.2019 KW - Electron probe microanalysis (EPMA) KW - Iridium-titanium mixed oxides KW - Spectroscopic ellipsometry KW - Mesoporous thin films PY - 2019 AN - OPUS4-48769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn T1 - Röntgenemission bei der UKP-Laser-Materialbearbeitung N2 - Der Vortrag stellt Untersuchungen im Rahmen eines BMBF-geförderten Vorhabens zur unerwünschten Röntgenemission bei der Materialbearbeitung mit ultrakurzen Laserpulsen vor. T2 - Seminar LEF - Laser in der Elektronikproduktion & Feinwerktechnik CY - Fürth, Germany DA - 26.02.2019 KW - Ultrakurze Laserpulse KW - Materialbearbeitung KW - Sekundärstrahlung KW - Röntgenemission KW - Laserschutz PY - 2019 AN - OPUS4-47468 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Pentzien, Simone A1 - Krüger, Jörg T1 - X-Ray Emission during Laser Processing with Ultrashort Laser Pulses N2 - Ultrashort laser pulse micromachining features a high precision. By increasing the repetition rate of the applied laser to several 100 kHz, laser processing becomes quick and cost-effective and make this method attractive for industrial applications. Upon exceeding a critical laser intensity, hard X-ray radiation is generated as a side effect. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose becomes significant for high-repetition-rate laser systems so that radiation safety must be considered. T2 - 5th UKP-Workshop: Ultrafast Laser Technology CY - Aachen, Germany DA - 10.04.2019 KW - Laser-induced X-ray emission KW - Radiation protection KW - Ultrashort laser material interaction PY - 2019 AN - OPUS4-47788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Peláez, R.J. A1 - Rebollar, E. A1 - Serna, R. A1 - Acosta-Zepeda, C. A1 - Saavedra, P. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Nanosecond laser-induced interference grating formation on silicon N2 - The formation of gratings on the surface of a silicon wafer by nanosecond laser irradiation through a phase mask using an ArF laser emitting at 193 nm is studied. The phase mask along with some focusing optics is capable to generate via interference a periodic intensity distribution, which can be used for surface patterning. The surface patterning strongly depends on the laser energy density and on the number of pulses, as revealed by atomic force microscopy (AFM). The results show that irradiation even with a single laser pulse produces periodic depth modulations on the surface. The spatial surface modulation is in the micrometer (1.7 µm) range while the depth modulation is in the nanometer regime (1–20 nm). With an increasing number of pulses (1–100), the depth modulation amplitude increases smoothly. Increasing the number of pulses further results in the progressive destruction of the grating, vanishing completely after ~5000 pulses. This evolution is also monitored in situ by measuring the intensity of the first order-diffracted probe beam and the behavior is in accordance with what is observed by AFM. Finally, we qualitatively explain the results invoking thermally induced effects in the melted Si: these physical processes involved are probably thermocapillary and/or Marangoni effects inducing material displacement as the surface melts. KW - Nanosecond laser irradiation KW - Silicon KW - Surface modification KW - Phase mask KW - Grating PY - 2019 UR - https://iopscience.iop.org/article/10.1088/1361-6463/ab0c5f DO - https://doi.org/10.1088/1361-6463/ab0c5f SN - 1361-6463 SN - 0022-3727 VL - 52 IS - 22 SP - 225302, 1 EP - 10 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-47619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Griepentrog, Michael A1 - Hertwig, Andreas A1 - Hielscher, Stefan A1 - Weise, Matthias T1 - Auf dem Weg zu Industrie 4.0: Bestimmung von Messunsicherheitsbudgets in der Oberflächentechnik N2 - Vorgestellt wurde die Bestimmung von Messunsicherheitsbudgets für sehr unterschiedliche physikalische Größen, die in der Oberflächentechnik von hoher Relevanz sind: Stufenhöhe h, Schichtdicke d, Eindringhärte HIT und Haftfestigkeit. Die Unterschiede betreffen die Art der Prüfmethodik (optisch zerstörungsfrei vs. mechanisch invasiv/zer-störend), die laterale Größe des Integrationsgebietes der Messung (lokal:nano bis sub-mikro vs. global: mikro bis makro) und die Art der Bestimmung von Messunsicherheitsbudgets (physikalische Größen: direkt rückführbar; Werkstoffkenngröße: genormt; Systemkenngröße: genormt). Im Rahmen von Industrie 4.0 werden ausgehend der geforderten Spezifikation des beschichteten Produkts (Mittelwert mit Vertrauensbereich oder Mindestwert) durchgehende Toleranzbänder zur Oberflächenmodifizierung/Beschichtung des Substrats, einhergehend mit Prozessfenstern, die diese Toleranzbänder garantieren, erforderlich, die zuverlässig erfasst werden müssen. Die Frage der anzuwendenden Mess- und Prüftechnik und die damit notwendige Betrachtung von Messunsicherheitsbudgets ist für die Digitalisierung von Konditionierungs-, Zustands-, Regel- und Steuergrößen unverzichtbar. Mit Blick auf die Einhaltung von Prozessfenstern und die dafür notwendige Prozessführung wird technologisches Kern-Know-how digitalisiert, das es unbedingt zu schützen gilt. Nur lokale Netze können diese Sicherheit garantieren, in globalen Netzen ist die Datensicherheit bestenfalls maximierbar. T2 - 14. ThGOT Thementage Grenz- und Oberflächentechnik CY - Zeulenroda, Germany DA - 12.03.2019 KW - Oberflächentechnik KW - Messunsicherheit KW - Messtechnik KW - Prüftechnik KW - Haftfestigkeit PY - 2019 AN - OPUS4-47612 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gawek, Marcel A1 - Madkour, Sherif A1 - Hertwig, Andreas A1 - Schönhals, Andreas T1 - Growth Kinetics and Molecular Mobility of Irreversibly Adsorbed Layers in Thin Films of P2VP and PVME N2 - In well-annealed thin polymer films, with non-repulsive polymer/substrate interactions, an irreversibly adsorbed layer is formed. These adsorbed layers have shown enormous potential for technological applications. Due to the hard accessibility of these layers, their growth kinetics and molecular dynamics are still not fully understood. Here, the irreversibly adsorbed layers of Poly(2-vinylpyridine) (P2VP) and Poly(vinyl methyl ether) (PVME) thin films are revealed by solvent-leaching experiments. The growth kinetics of these layers is investigated as a function of original film thickness and annealing times. The thickness, topography and quality of the adsorbed layer is determined with Atomic Force Microscopy (AFM) and spectroscopic ellipsometry. Additionally, the molecular mobility of the adsorbed layer is investigated with Broadband Dielectric Spectroscopy (BDS). A recently developed nanostructured capacitor (NSC) is employed to measure the adsorbed layers with a free surface layer depending on annealing and solvent-leaching time. The results are quantitatively compared and discussed with respect to recently published work. T2 - Spring Meeting of German Physical Society CY - Regensburg, Germany DA - 31.03.2019 KW - Adsorbed layer KW - Thin polymeric films PY - 2019 AN - OPUS4-47766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Quo vadis LIPSS? – Applications of laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 VL - 3/1 SP - 41 EP - 43 PB - Hochschule Mittweida CY - Mittweida AN - OPUS4-49673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn T1 - X-ray emission during ultrashort pulse laser processing N2 - The industrial use of ultrashort laser pulses has made considerable progress in recent years. The reasons for this lie in the availability of high average powers at pulse repetition rates in the several 100 kHz range. The advantages of using ultrashort laser pulses in terms of processing precision can thus be fully exploited. However, high laser intensities on the workpiece can also lead to the generation of unwanted X-rays. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose can become significant for high-repetition-rate laser systems so that X-ray exposure safety limits must be considered. The X-ray emission during ultrashort pulse laser processing was investigated for a pulse duration of 925 fs at 1030 nm wavelength and 400 kHz repetition rate. Industrially relevant materials such as steel, aluminum and glass were treated. Tungsten served as reference. X-ray spectra were recorded, and X-ray dose measurements were performed for laser treatment in air. For laser intensities > 2 × 10^13 W/cm2, X-ray doses exceeding the regulatory exposure limits for members of the public were found. Suitable X-ray protection strategies are proposed. T2 - SPIE Photonics West CY - San Francisco, USA DA - 02.02.2019 KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Radiation protection PY - 2019 AN - OPUS4-47361 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Griepentrog, Michael A1 - Hertwig, Andreas A1 - Hielscher-Hofinger, Stefan A1 - Weise, Matthias T1 - Mechanische, topometrische und optische Charakterisierung von Schichten mit Stand der Normung N2 - Der Vortrag „MECHANISCHE, TOPOMETRISCHE UND OPTISCHE CHARAKTERISIERUNG VON SCHICHTEN MIT STAND DER NORMUNG“ widmet sich unterschiedlichen Beschichtungssystemen und deren mechanischer, topometrischer und optischer Charakterisierung. Über die entsprechenden aktuellen Normen wird informiert. Es betrifft Verfahren wie die Instrumentierte Eindringprüfung (IIT), Centrifugal Adhesion Testing, Weißlichtinterferenzmikroskopie, Tastschnittverfahren und Ellipsometrie (SE). T2 - EFDS, V2019, Vakuum und Plasma CY - Dresden, Germany DA - 08.10.2019 KW - Normung KW - Spektrale Ellipsometrie (SE) KW - Instrumentierte Eindringprüfung (IIT) KW - Centrifugal Adhesion Testing (CAT) KW - Weißlichtinterferenzmikroskopie (WLIM, 3D) PY - 2019 AN - OPUS4-49320 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Scanning White Light Interference Microscopy - Measurement of Topometry and Layer Thickness N2 - 3D coherence scanning interferometry (CSI) is anoptical, non-contact and rapide measurement technique using a defined bandwidth of white light at normal incidence. White light interference microscopy (WLIM) providest here-dimensional surface topometry data up to a resolution of 0.4 µm lateral and 0.1 nm vertical. Three operating modi, surface, films and advanced films, enable measurements of step heights, roughness, wear volume, cone angle, surface pattern and layer thickness. Traceability to SI system is ensured by certified standards (PTB/NIST) within a DAkkS DIN EN ISO/IEC 17025:2018 accredited lab. T2 - EFDS, V2019, Vakuum und Plasma, WS 4, Beschichtungen für Werkzeuge & Bauteile CY - Dresden, Germany DA - 08.10.2019 KW - DIN EN ISO/IEC 17025:2018 KW - Certified standards KW - White light interference microscopy(WLIM) KW - 3D coherence scanning interferometry (CSI) KW - Topometry PY - 2019 AN - OPUS4-49323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission during ultrashort pulse laser processing N2 - The industrial use of ultrashort laser pulses has made considerable progress in recent years. The reasons for this lie in the availability of high average powers at pulse repetition rates in the several 100 kHz range. The advantages of using ultrashort laser pulses in terms of processing precision can thus be fully exploited. However, high laser intensities on the workpiece can also lead to the generation of unwanted X-rays. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose can become significant for high-repetition-rate laser systems so that X-ray exposure safety limits must be considered. The X-ray emission during ultrashort pulse laser processing was investigated for a pulse duration of 925 fs at 1030 nm wavelength and 400 kHz repetition rate. Industrially relevant materials such as steel,aluminum and glass were treated. Tungsten served as reference. X-ray spectra were recorded, and X-ray dose measurements were performed for laser treatment in air. For laser intensities > 2 × 10^13 W/cm2, X-ray doses exceeding the regulatory exposure limits for members of the public were found. Suitable X-ray protection strategies are proposed. T2 - SPIE Photonics West CY - San Francisco, USA DA - 02.02.2019 KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Radiation protection PY - 2019 SN - 978-1-5106-2459-7 DO - https://doi.org/10.1117/12.2516165 SN - 0277-786X SN - 1996-756X VL - 10908 SP - 1090802-1 EP - 1090802-7 PB - SPIE - The international society for optics and photonics CY - Bellingham, WA, USA AN - OPUS4-47510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Höhm, S. A1 - Derrien, Thibault J.-Y. A1 - Krüger, Jörg T1 - Laser-induced periodic surface nanostructures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers and show a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Symposium “Fundamentals of Laser Assisted Micro- and Nanotechnologies” (FLAMN-19) CY - St. Petersburg, Russia DA - 30.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Ultrafast scattering PY - 2019 AN - OPUS4-48420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Krüger, Jörg T1 - Emission von Röntgenstrahlung bei der UKP-Laser-Materialbearbeitung N2 - Der Vortrag stellt Untersuchungen im Rahmen eines BMBF-geförderten Vorhabens zur unerwünschten Emission von Röntgenstahlung bei der Materialbearbeitung mit ultrakurzen Laserpulsen vor. T2 - 7. OptoNet Laserstammtisch “Ultrakurzpulslaser” CY - Jena, Germany DA - 12.03.2019 KW - Laserschutz KW - Materialbearbeitung KW - Röntgenemission KW - Sekundärstrahlung KW - Ultrakurze Laserpulse PY - 2019 AN - OPUS4-47569 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures: from light localization to applications N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Conference on Advanced Laser Technologies (ALT'19) CY - Prague, Czech Republic DA - 15.09.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Electromagnetic scattering PY - 2019 AN - OPUS4-49098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures: from nanoscaled light localization to applications N2 - In this contribution the current state in the field of Laser-Induced Periodic Surface Structures (LIPSS) is reviewed. This includes the mechanisms of formation and current applications, particularly the colorization of technical surfaces, the control of surface wetting properties, the tailoring of surface colonization by bacterial biofilms, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - PHOTONICA 2019 - The Seventh International School and Conference on Photonics CY - Belgrade, Serbia DA - 26.08.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Surface functionalization PY - 2019 UR - http://www.photonica.ac.rs/docs/PHOTONICA2019-Book_of_abstracts.pdf AN - OPUS4-48836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Surface functionalization by laser-induced periodic surface structures N2 - In recent years, the improved understanding of the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical and chemical properties of many materials. Such structures strongly depend on the laser beam polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. The most accepted explanation for the origin of the structures is based on the interference of the incident laser radiation with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periods ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelength, pulse duration and repetition rate laser sources, customized micro- and nanometric spatial resolutions, and the compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces and bacterial and cell growth for medical devices, among many others. T2 - 38th International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Surface functionalization KW - Applications PY - 2019 SN - 978-1-940168-1-42 SP - Paper Nano 404 AN - OPUS4-50070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Krüger, Jörg T1 - Quo vadis LIPSS? – Recent developments in theoretical modelling and technical applications N2 - This presentation reviews current and expected developments in the field of laser-induced periodic surface structures (LIPSS, ripples). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying laser material processing applications. The structures can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their spatial periods typically range from several micrometers down to less than 100 nanometers, exhibiting a clear correlation with the polarization direction of the laser radiation used. Various types of LIPSS have been classified, relevant control parameters were identified, and material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Special attention will be paid to a comparison of the currently available formation theories for LIPSS with a discussion of their respective strengths and weaknesses. Currrently explored applications featuring surface functionalization in the fields of optics, surface wetting, medicine, and tribology will be discussed. T2 - 9th International LIPSS Workshop CY - Ljubljana, Slovenia DA - 26.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Femtosecond laser ablation KW - Modelling KW - Applications PY - 2019 AN - OPUS4-49708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Hodoroaba, Vasile-Dan A1 - Braun, Ulrike A1 - Pfeifer, Dietmar A1 - Sturm, Heinz T1 - Reinforced UV curable cycloaliphatic epoxy oligosiloxane resin nanocomposite for coating applications N2 - Coating materials are nowadays often required to deliver not only sufficient barrier performance and suited optical appearance but a broad range of other functional properties. The incorporation of inorganic nanoparticles (NPs) is known to improve many key characteristics and provide new functionalities in polymer materials. Presented work aims to prepare and characterize an organic-inorganic coating material designed to bring together advantageous properties of hybrid materials and reinforcement effect delivered from the inorganic NPs embedment. Siloxane-based hybrid resins hold great advantages as coating materials as their properties can be tuned between those of polymers and those of glasses, thus, the compositions with superior thermal and mechanical properties can be achieved. We used Cycloaliphatic Epoxy Oligosiloxane (CEOS) resin as a polymeric matrix where the network formation was achieved by UV induced cationic polymerisation. Boehmite Alumina (BA) nanoparticles were added to CEOS resin as a reinforcing agent and resultant material was processed into films either by bar-coating or by spin-coating depending on further characterization procedure. Two different types of BA NPs, hydrophilic and organophilic, were used in order to assess the impact of particles surface on the resin characteristics. CEOS synthesis by condensation reaction was confirmed using 13C and 29Si NMR. Changes in CEOS photocuring process, resulting from particles incorporation, were monitored by real-time IR spectroscopy. At the same time, the thermal behaviour was evaluated by DSC and TGA methods. Morphology of the coatings was investigated by means of SEM operated in transmission mode. It was observed that BA presence increased the epoxy conversion degree and glass transition temperature. Material formulations providing best film characteristics were determined with regard to the particle type and loading. Compared to the hydrophilic nanoparticles, organophilic BA NPs yield superior overall performance of the foils. T2 - HYMA Conference CY - Sitges, Spain DA - 11.03.2019 KW - Cycloalyphatic epoxy oligosiloxane KW - Nanocomposite KW - Boehmite KW - Photocuring PY - 2019 AN - OPUS4-47641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of rheology modifying admixtures on early hydration of cementitious suspensions N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has enormous influence on the early hydration of cement. C3A as the most reactive phase of Portland cement plays a significant role in early hydration reactions and affects the rheological performance. Therefore, this paper presents experimental results about the influence of delayed addition of PCEs on the Hydration of cement and C3A-gypsum pastes investigated by isothermal heat flow calorimetry. Complementary in-situ XRD was carried out on C3A pastes to analyze hydration and phase changes related to the addition of PCE. Cement pastes with a delayed addition of PCE showed less Retardation compared to simultaneous addition. The alteration caused by PCE is much more pronounced for C3A-gypsum mixes. With a delayed addition of SP, the hydration of C3A is less retarded or even accelerated. It is obvious that there is less retardation the later the addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and hydration rates. XRD results showed that more C3A is dissolved in the presence of PCE. Also, the gypsum depletion occurs earlier in the presence of PCE and even faster with delayed addition. Without PCE AFm starts to form just after the gypsum depletion. However, in the presence of PCE AFm already starts to form at the beginning of the hydration. Due to the faster gypsum depletion in the presence of PCE, also the transformation from ettringite into AFm begins earlier, but takes longer as without SP. T2 - 15th International Congress on the Chemistry of Cement CY - Prague, Czech Republic DA - 16.09.2019 KW - Cement KW - C3A KW - Early hydration KW - Polycarboxylate ether (PCE) KW - Delayed addition PY - 2019 SP - 1 EP - 8 AN - OPUS4-49104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Quo vadis LIPSS? – Applications of Laser-Induced Periodic Surface Structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zutta Villate, J. M. A1 - Hahn, Marc Benjamin T1 - Radioactive gold nanoparticles for cancer treatment N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. KW - Gold KW - Nanoparticle KW - Cancer KW - Monte-Carlo KW - Simulation KW - Cluster PY - 2019 DO - https://doi.org/10.1140/epjd/e2019-90707-x SN - 1434-6060 SN - 1434-6079 VL - 73 IS - 95 SP - 1 EP - 7 PB - Springer CY - Berlin AN - OPUS4-47964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Acosta-Zepeda, C. A1 - Saavedra, P. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Modeling of silicon surface topographies induced by single nanosecond laser pulse induced melt-flows N2 - Irradiation with a single nanosecond laser pulse in the melting regime can result in a characteristic change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In this work, the dimple height, depth, and width are modeled following and extending in a more rigorous manner the approach of Wood and Giles [Phys. Rev. B 23, 2923–2942 (1981)] and that of Schwarz-Selinger and coworkers [Phys. Rev. B 64, 155323 (2001)], upon varying the laser irradiation parameters such as peak energy density, pulse duration, and wavelength. This is achieved with numerical simulations of one-dimensional heat flow as input to the analytical fluid-flow equations. KW - Nanosecond laser KW - Melting KW - Silicon KW - Fluid-flow PY - 2019 DO - https://doi.org/10.1063/1.5053918 SN - 0021-8979 SN - 1089-7550 VL - 125 IS - 17 SP - 175101-1 EP - 175101-9 PB - AIP Publishing CY - Melville, USA AN - OPUS4-47927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - A survey of surface functionalization through laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, the advancement of medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - Seminar, ALPhANOV - Centre Technologique Optique et Lasers CY - Talence, France DA - 07.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Surface functionalization KW - Applications KW - Femtosecond laser PY - 2019 AN - OPUS4-48199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - Seminar CY - Laser-Laboratorium Göttingen e.V., Germany DA - 18.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Electromagnetic radiation KW - Applications KW - Femtosecond laser ablation PY - 2019 AN - OPUS4-49689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Wirth, Thomas A1 - Florian, Camilo A1 - Sturm, Heinz A1 - Spaltmann, Dirk A1 - Krüger, Jörg T1 - Chemical effects during the formation of femtosecond laser-induced periodic surface structures N2 - The processing of laser-induced periodic surface structures (LIPSS, ripples) on metals and semiconductors in ambient air is usually accompanied by superficial oxidation effects – a fact that is widely neglected in the current literature. In this contribution, chemical, structural, and mechanical alterations in the formation of femtosecond LIPSS are characterized by a variety of surface analytical techniques, including energy dispersive X-ray analyses (EDX), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy (µ-RS), and depth-profiling Auger electron microscopy (AEM). Alternative routes of electrochemical and thermal oxidation allow to qualify the relevance of superficial oxidation effects on the tribological performance in oil lubricated reciprocating sliding tribological tests (RSTT). It is revealed that the fs-laser processing of near-wavelength sized LIPSS on metals leads to the formation of a few hundreds of nanometers thick graded oxide layers, consisting mainly of amorphous oxides. Regardless of reduced hardness and limited thickness, this nanostructured surface layer efficiently prevents a direct metal-to-metal contact in the RSTT and may also act as an anchor layer for specific wear-reducing additives contained in the used engine oil. T2 - EMRS Spring Meeting 2019, Symposium V “Laser interactions with materials: from fundamentals to applications" CY - Nice, France DA - 27.05.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Oxidation KW - Tribology PY - 2019 AN - OPUS4-48127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. A1 - Kunz, C. A1 - Büttner, T.N. A1 - Naumann, B. A1 - Boehm, A.V. A1 - Gnecco, E. A1 - Bonse, Jörn A1 - Neumann, C. A1 - Turchanin, A. A1 - Müller, F.A. T1 - Large-area fabrication of low- and high-spatial-frequency laser-induced periodic surface structures on carbon fibers N2 - The properties of fiber-reinforced polymers (CFRP) or concretes (ECC) strongly depend on the interface between the fiber and the surrounding matrix. Different methods such as plasma oxidation, chemical or electrolytic etching and chemical vapor deposition have been investigated to increase, for example, the bonding strength. The present study deals with the functionalization of the fiber surface based on laser-induced periodic surface structures (LIPSS). They can be characterized as a modulation of the surface topography on the nano- and microscale that results from the irradiation of the surface with linearly polarized laser radiation close to the ablation threshold. According to their spatial period, LIPSS are classified into low-spatial frequency LIPSS (LSFL) and high-spatial frequency LIPSS (HSFL). The great potential of both types of LIPSS structures regarding functional surface properties was demonstrated in numerous investigations. The objective of the present study was the homogenous manufacturing of both types of LIPSS on large areas of carbon fiber arrangements without damage. The results are discussed based on a detailed analysis of the topographic and chemical surface properties. T2 - 15th International Conference on Laser Ablation (COLA 2019) CY - Hawaii, USA DA - 08.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Carbon fibers KW - Femtosecond laser ablation KW - Surface functionalization PY - 2019 AN - OPUS4-49676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee T1 - Grenzflächen als Material: Konzepte und Beispiele zu nanoverstärkten Duroplasten N2 - Nachdem Jahrzehnte die Grenzfläche zwischen Kohlefaser und Duroplastmatrix optimiert wurde liegt das Augenmerk heute auf der Polymermatrix selbst. Diese lässt sich hinsichtlich ihres Elastizitätsmoduls und ihrer Bruchfestigkeit verbessern, indem Nanopartikel aus Böhmit (AlOOH) eindispergiert werden. Der Vortrag geht auf integrale und hochauflösend-bildgebende Methoden ein die ein Verständnis der komplexen Zusammenhänge ermöglichen. Nach einer chemischen in-situ Analyse des Aushärtvorgangs, aus welchem sich die Bedeutung der externer Parameter ablesen lässt, werden diverse hochauflösende, neue Methoden der Rasterkraftmikroskopie (AFM) eingeführt. Der lokalen Bestimmung des E-Moduls der Nanopartikel folgen Ausführungen zum temperaturabhängigen Chemismus des Böhmits, der während der Aushärtung Wasser freisetzt. Die hochauflösende Bestimmung der Oberflächenpotentiale, der Steifigkeit, der attraktiven Kräfte zwischen Spitze und Probe sowie der Energiedissipation im Kontakt stellen auf der Nanoskala eine komplexe Datenquelle dar, die auf der Makroskala einer Ergänzung bedarf: Durch Kombination von dynamisch-mechanisch-thermischer Analyse einerseits und Kartierung physikalischer Eigenschaften auf der Nanoskala andererseits kann der Zusammenhang zwischen chemischer Steuerung der Netzwerkbildung und den mechanischen Eigenschaften des Nanokomposits geklärt werden. Überraschend ist, dass bei geeigneter Steuerung der lokale E-Modul der Polymermatrix den des Füllstoffs übersteigt. Die Rissfortschrittsenergie wird in Böhmit-modifiziertem Epoxy verbessert absorbiert, die These dazu ist, dass die (010)-Gleitebenen, die nur durch Wasserstoffbrücken zusammen gehalten werden, einigermaßen schadlos geschert werden können. Daraus folgt, dass das System auf der Nanoskala über einen, wenn auch begrenzten, Selbstheilmechanismus verfügt. Zudem wird durch die hohe Heterogenität der Steifigkeit und Energiedissipation des Nanokomposits eine Risstrajektorie vielfach umgelenkt und somit früher gestoppt. Ergebnisse dieses Vortrags stammen aus einer Zusammenarbeit innerhalb des DFG-Forscherverbundes FOR2021 „Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtbau“. T2 - Niedersächsisches Symposium Materialtechnik - NSM 2019 CY - Clausthal, Germany DA - 14.02.1019 KW - Nanokomposit KW - Böhmit KW - Risstrajektorie KW - Oberflächenpotential KW - Energiedissipation im Kontakt KW - Oberflächensteifigkeit KW - attraktive Wechelwirkung KW - Epoxy-Anhydrid Duroplast KW - Leichtbau PY - 2019 AN - OPUS4-47636 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Ghasem Zadeh Khorasani, Media A1 - Hodoroaba, Vasile-Dan A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Versatile role of boehmite particles in epoxy-based nanocomposites N2 - Thermosetting materials are gaining increasing attention in many structural composite applications. However, the incorporation of inorganic nanoparticles (NPs) into polymer matrix is a promising approach to enhance their functional characteristics, and thus, to enable the development of thermosets advanced application. It has been shown that Boehmite Alumina (BA) used as nanofillers can improve different parameters of polymers. This NPs can be easily tailored enabling desirable interactions with a big range of polymers. However, the overall effect of nanofiller depends on many factors, therefore, making it hard to predict the resulted performance of nanocomposites. In the current contribution we would like to discuss the impact of Boehmite NPs on two different epoxy resin nanocomposite systems with the focus on the possible influence mechanisms of this nanofiller. As the first system, UV curable Cycloaliphatic-Epoxy Oligosiloxane (CEOS) resin/Boehmite nanocomposites were investigated by FTIR, TGA, DSC and T-SEM. It was observed that incorporation of BA leads to the reinforcement of glass transition (Tg) and overall thermal stability indicating the attractive interactions between BA and CEOS network. In addition, an increase in epoxy conversion of CEOS was concluded for nanocomposites assuming that particles are involved in UV polymerisation processes. The second epoxy/Boehmite nanocomposite is based on the bisphenol-A-diglycidyl ether (DGEBA) cured with methyl tetrahydrophtalic acid anhydride (MTHPA). Thermomechanical as well as nanomechanical properties of this material were investigated by DMTA and IR spectroscopy and the advanced Intermodulation AFM, respectively. In contrast to the first system, it was found that BA leads to a decrease of Tg and crosslink density of the polymer while the young’s modulus of the composite and local stiffness of polymer matrix increase significantly. As a result, the versatile role of Boehmite was detected depending on the investigated systems. Based on the obtained results, the parameters indicating property-efficient epoxy/Boehmite system are suggested. T2 - HYMA Conference CY - Sitges, Spain DA - 11.03.2019 KW - Epoxy KW - Boehmite KW - Curing KW - Nanocomposite PY - 2019 AN - OPUS4-47640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Mechanical and chemical alteration of polymer matrix induced by nanoparticles in epoxy-boehmite nanocomposites N2 - Inorganic nanoparticles are used to improve the performance of epoxy as the matrix phase in fiber-reinforced composites used for aerospace applications. The effectiveness of nanofillers on property enhancement of thermosetting polymers depends on many factors including the interaction between the functional groups of nanofillers and the polymer reactants. In the current work, we study the effect of boehmite nanoparticles (BNPs) on properties of anhydride-cured bisphenol-A-diglycidyl ether (DGEBA). Dynamic mechanical thermal analysis (DMTA) and a high-resolution force measurement approach called intermodulation atomic force microscopy (ImAFM) were carried out to investigate the thermomechanical and nanomechanical properties of this material, respectively. It was found that BNPs lead to decrease of glass transition temperature (Tg) and crosslink density of the polymer network meanwhile significantly enhancing the Young’s modulus. Besides formation of a soft interphase near the particles, significant changes in local stiffness of polymer matrix far from the interphase was observed with ImAFM. Thus, boehmite induces long-range chemical alteration on the matrix. This effect has a higher impact on overall composite properties compared to the formation of interphase which is only a short-range effect. The local chemical evaluations on the soft interphase using an infrared-AFM method (NanoIR) revealed the accumulation of anhydride hardener near the boehmite interface. Based on these observations the effect of boehmite on the curing of epoxy is hypothesized to be governed by the strong interaction between boehmite and the anhydride. This interaction causes changes the ratio of reactants in the epoxy mixture and hence alteration of curing pathway and the network architecture. In future studies we examine this hypothesis by measuring the thermomechanical properties of cured epoxies in which the epoxy-hardener ratio is systematically altered and further comparing to those properties of nanocomposites shown in the current study. T2 - HYMA 6th International Conference on Multifunctional, Hybrid and Nanomaterials CY - Sitges, Spain DA - 11.03.2019 KW - Nanomechanics KW - Polymer nanocomposites KW - Boehmite KW - AFM KW - Epoxy PY - 2019 AN - OPUS4-50692 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Braun, Ulrike T1 - Kunststoffe und deren Recycling – Materialwissenschaftliche Erkenntnisse, um mehr Recyclat einzusetzen N2 - Nach einer Übersicht zu den immer schneller aktualisierenden Rahmenbedingungen von Politik und Gesellschaft folgt eine Übersicht zu materialwissenschaftlichen Problemen des Recyclings von Kunststoffen. Lösungsansätze aus der Forschung reichen von einfacher Optimierung bis hin zur radikalen Neukonstruktion der polymeren Werkstoffe. Aus dem bereits möglichen Ansatz "performance-by-design" wird ein neuer Weg des "recycling-by-design" adressiert. Dies inkludiert methodisch eine skalenübergreifende Modellierung und die Depolarisation bis zum Monomer. T2 - Gefahrgut-Technik-Tage CY - Berlin, Germany DA - 07.11.2019 KW - Recycling KW - Kunststoff KW - Additiv KW - Polymer KW - Normung KW - Plastikstrategie KW - Grenzfläche als Material KW - Recycling-by-design PY - 2019 AN - OPUS4-49561 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Applications on Surface Functionalization by Laser-Induced Periodic Surface Structures (LIPSS) N2 - In recent years, the understanding on the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical and chemical properties of many materials. Such structures strongly depend on the used polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. Some specific formation mechanisms to explain every situation are still to be uncovered, but the most accepted explanation relies on the interference of the incident laser beam with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periodicities ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelength, pulse duration and repetition rate laser sources, customized micro- and nanometric spatial resolutions and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces and bacterial and cell growth for medical devices among many others. T2 - 38th International Congress on Applications of Lasers and Electro Optics (ICALEO 2019) CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard A1 - Topolniak, Ievgeniia A1 - Schenderlein, Matthias A1 - Sturm, Heinz T1 - Nano polymer (composite) printing N2 - This talk introduces the PolyPoly, a new device at BAM which enables the three-dimensional structuring of polymer nanocomposites with an extremely high resolution of 150x150x600 nm. Initial examples and findings will be shown. T2 - BAM-IFW Workshop CY - Dresden, Germany DA - 28.03.2019 KW - Multiphoton laser structuring KW - Polymer nanocomposites KW - 3d structuring KW - Additive manufacturing PY - 2019 AN - OPUS4-48041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Undisz, A. A1 - Kirner, Sabrina V. A1 - Spaltmann, Dirk A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Oxidation effects on the functionality and formation of laser-induced periodic surface structures N2 - In the last decades, the formation of laser-induced periodic surface structures (LIPSS) has been widely studied, not only to stablish a general understanding of the main mechanisms present during the irradiation with ultrashort laser pulses, but also to identify the main processing parameters for its fabrication on various technical materials. However, an important and almost always present effect that is typically set aside is the material oxidation during or after the laser processing. Usually, this leads to optical, chemical, structural and mechanical alterations that are seldomly studied in detail. Therefore, in this work we present a study that includes the formation of LIPSS on Ti6Al4V alloy for tribological applications were different oxidations layers are involved. The material characterization using different techniques, such as energy dispersive X-ray analyses (EDX), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy (µ-RS), and depth-profiling Auger electron microscopy (AEM), and other techniques, confirms the formation of a non-negligible superficial oxide layer – strongly dependent on the specific processing parameters. We perform tribological experiments on laser irradiated samples oxidized by alternative ways to have a comparison on its friction performance. The obtained results show significant differences that depend directly on the thickness and the quality of the oxidized layer. This may open a fertile research area until now barely explored with clear impact on LIPSS based applications. T2 - 9th International LIPSS Workshop CY - Ljubljana, Slovenia DA - 26.09.2019 KW - Laser-induced periodic surface structures (LIPSS) PY - 2019 AN - OPUS4-49709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fortini, Renata A1 - Sturm, Heinz A1 - Meyer-Plath, Asmus A1 - Kehren, Dominic T1 - Development of a method for measuring the flexural rigidity of nanofibers N2 - Toxicological studies have shown that some types of carbon nanotubes may provoke asbestos-like effects including chronic inflammation and lung cancer. Inhaled carbon nanotubes may reach the deep lung tissue. Alveolar macrophages are responsible to remove such foreign objects from the alveoli in a process called phagocytosis. If a macrophage fails to uptake a nanotube completely, cell lesions give rise to inflammation. It is currently assumed that short, long and flexible, and granularly agglomerated (tangled) nanofibres are clearable by macrophages, whereas biodurable long and rigid nanotubes persist in the lung tissue. The flexural rigidity of nanofibres is therefore believed to an important material property that governs fibre toxicity and needs to be investigated. The present work aims at determining the rigidity of nanofibres by detecting their resonance frequencies using a Dynamic Scanning Electron Microscope (DySEM) setup. By depositing and fixing a nanofibre to an oscillating support, it can be excited to vibrations and treated as a cantilevered beam. This way, its elastic modulus can be determined via Euler-Bernoulli’s beam theory. Multi-walled carbon nanotubes (MWCNTs) were deposited on high frequency piezoelectric quartz crystals mounted on a scanning electron microscope (SEM) holder. When introduced into the SEM chamber and connected to a frequency-sweeping waveform generator, the quartz crystal actuates the deposited fibre. A lock-in amplified processes the secondary electron detector signal resulting from the electron beam modulated by the vibrating nanofibre. Whenever a fibre resonance is detected, the SEM image of the fibre is stored to identify the fibre oscillation mode. The found resonance frequencies and modes allow determining the elastic modulus according. Since the frequency spacing of resonances is predicted by Euler-Bernoulli, the mode number can be checked and elastic modulus values be averaged. A significant number of MWCNTs have been classified according to their level of rigidity. The applicability and reliability of the method will be discussed. T2 - International Conference on Multifunctional, Hybrid and Nanomaterials CY - Sitges, Spain DA - 11.03.2019 KW - Carbon nanotubes KW - Rigidity KW - Resonance KW - Nanofibers KW - Bending modulus PY - 2019 AN - OPUS4-49196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Zarinwall, A. A1 - Silbernagl, Dorothee A1 - Garnweitner, G. A1 - Sturm, Heinz T1 - Mechanical coupling of matrix and nanoparticles depending on particle surface modification N2 - Boehmite nanoparticles has been successfully functionalized with APTES. After APTES functionalization further modification with tailored molecules e.g. via carboxylic acids is possible. The tailored surface functionalization is strongly enhanced by improved coupling protocols. Arbitrary variation of the functionalization degree is possible. Thereby the temperature stable APTES functionalization enables a wide range of functional groups. By TGA-MS analysis strong evidence for the bonding situation of the APTES on the boehmite surface has been found. Additionally first experiments has been performed to predict the polymer-particle compatibility enhancement via reverse wetting angle measurements with AFM. T2 - Workshop Acting Principles of Nano-Scaled Matrix Additives for Composite Structures CY - BAM, Berlin, Germany DA - 11.10.2019 KW - Surface modification KW - Nanocomposites KW - Boehmite KW - Silane KW - Thermogravimetry KW - Mass spectrometry PY - 2019 AN - OPUS4-49435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of rheology modifying admixtures on early hydration of cementitious suspensions N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has enormous influence on the early hydration of cement. C3A as the most reactive phase of Portland cement plays a significant role in early hydration reactions and affects the rheological performance. Therefore, this talk presents experimental results about the influence of delayed addition of PCEs on the Hydration of alite and C3A-gypsum pastes investigated by isothermal heat flow calorimetry. Complementary in-situ XRD was carried out on C3S and C3A-gypsum pastes to analyze hydration and phase changes related to the addition of PCE. Cement pastes with a delayed addition of PCE showed less retardation compared to simultaneous addition. The alteration caused by PCE is much more pronounced for C3A-gypsum mixes. With a delayed addition of SP, the hydration of C3A is less retarded or even accelerated. It is obvious that there is less retardation the later the addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and Hydration rates. XRD results showed that more C3A is dissolved in the presence of PCE. Also, the gypsum depletion occurs earlier in the presence of PCE and even faster with delayed addition. Without PCE AFm starts to form just after the gypsum depletion. However, in the presence of PCE AFm already starts to form at the beginning of the hydration. Due to the faster gypsum depletion in the presence of PCE, also the transformation from ettringite into AFm begins earlier, but takes longer as without SP. T2 - 15th International Congress on the Chemistry of Cement CY - Prague, Czech Republic DA - 16.09.2019 KW - Cement KW - Alite KW - C3S KW - C3A KW - Early hydration KW - Polycarboxylate ether (PCE) KW - Delayed addition PY - 2019 AN - OPUS4-49103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -