TY - RPRT A1 - Beck, Uwe A1 - Stockmann, Jörg M. T1 - AiF Projekt GmbH, KONTRAST – schnell, sicher, sichtbar N2 - Das Projekt KONTRAST adressiert die Qualitätskontrolle (QC) zur Erfassung nano- und mikroskaliger Belegung/Degradation mittels abbildender Ellipsometrie (IE). Das BAM-Teilvorhaben beinhaltet das Screening von Benchmark-Materialsystemen und die Validierung von Messstrategien. Im Ergebnis erfolgte eine Fokussierung auf das im Vergleich zur off Null Ellipsometrie (ONE) aussichtereichere Verfahren der referenzkompensierten Ellipsometrie(RKE), das marktstrategisch in RSE (referenced spectral ellipsometry) umbenannt wurde. Alle Materialsysteme der BAM-Unterauftragnehmer konnten mit IE visualisiert werden, mit dem RSE-System in wesentlich kürzeren Zeiten, auf größeren Flächen, bei vergleichbarer Empfindlichkeit und Auflösung, Komplementärverfahren waren für den schnellen Nachweis nano- und mikroskaliger Belegung nicht konkurrenzfähig, wobei zusätzliche Materialsysteme mit niedrigem Kontrast (SnO:Ni auf Glas bzw. Cr auf Chromstahl) in der BAM hergestellt wurden. Die öffentliche Präsentation des RSE-Prototyps erfolgte auf der ICSE-7 2016 mit der Publikation 2017 in Applied Surface Science. KW - Abbildende Ellipsometrie (IE) KW - Imaging Null Ellipsometrie (INE) KW - Referenced Spectral Ellipsometry (RSE) KW - Oberflächenverunreinigungen KW - Visualisierung bei geringem Kontrast PY - 2017 N1 - Das Dokument unterliegt der Vertraulichkeit und kann nicht zugänglich gemacht werden Projektlaufzeit: 01.10.2014 bis 28.08.2017 The document is subject to confidentiality restrictions and cannot be made accessible Project runtime: 01.10.2014 to 28.08.2017 SP - 1 EP - 16 AN - OPUS4-50420 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghasem Zadeh Khorasani, Media T1 - Long range influence of boehmite nanoparticles on the nanomechanics of epoxy matrix used in carbon-fiber composites N2 - Boehmite nanoparticles (AlOOH) were recently found to improve properties such as crack resistance, shrinkage and compressive strength in epoxy composites. Concentration and surface modification of boehmite nanoparticles are key factors for abovementioned enhancements. To understand the underlying mechanisms, more detailed research of micro- and nanoscopic mechanical properties is required. The presented study aims to investigate the influence of concentration and surface modification of boehmite on the stiffness of the bulk epoxy by means of AFM-based approaches: Force-Distance curves (FDC) on the sub- microscale and Intermodulation AFM and amplitude-dependent force spectroscopy (ADFS) on the nanoscale. For this purpose, stiffness-maps of epoxy filled with boehmite, with and without surface modification (HAc-boehmite) were obtained by FDC. These measurements showed a slight increase in overall stiffness of composite with increasing the nanoparticle content. The stiffening effect was observed to be intensified with HAc-boehmite. Since the lateral resolution of FDC is not high enough to distinguish nanoparticles, this effect was assumed to be due to the inevitable inclusion of nanoparticles in the measurement. By using Intermodulation-AFM, yielding ADFS stiffness maps with the resolution of <10 nm, we were able to calculate the average stiffness of bulk epoxy without the interference of nanoparticles. It was expected that the stiffness of regions faraway from particles would be equal to neat epoxy. In contrast, the results showed a drastic increase in stiffness of epoxy with increasing boehmite concentration (0, 1, 2.5, and 15%) especially in case of introducing 15wt% HAc-boehmite. Another important observation was formation of a spatial structure with non-homogenous stiffness distribution in bulk epoxy with HAc-boehmite. The underlying mechanisms of described observations are not fully understood yet. One hypothesis is the local increase in crosslinking density which we aim to investigate in our further studies by combining Dynamic Mechanical Thermal Analysis (DMTA) and Intermodulation-AFM. T2 - Frontiers in Polymer Science CY - Seville, Spain DA - 17.05.2017 KW - AFM KW - Boehmite KW - Epoxy nanocomposite PY - 2017 AN - OPUS4-50688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghasem Zadeh Khorasani, Media T1 - Studies on interphase formation of cured epoxy resin near boehmite surface N2 - The application of inorganic nanoparticles as reinforcement agent for polymer composites is constantly growing. Improving the performance of the material with desirable properties requires understanding of the interaction between polymer chains and nanoparticles and the properties of the interphase as well. Boehmite, a mineral of aluminum with basic unit of AlO(OH), is a novel and promising nanofiller which leads to enhanced performance of polymer composites. It has been recently reported that boehmite nanoparticles have reinforcing effect on epoxy matrix in carbon-fiber composites. It was primarily assumed that these improvements are due to very high Young’s modulus of boehmite particles. However, in our latest study we presented new values for the Young’s modulus of boehmite much lower than those reported earlier. This brings up the importance of interphase properties, e.g. the crosslink density, which can have the dominant role in the overall material property. Nevertheless, due to resolution limitations of conventional nanoprobing approaches, characterization of the interphase between individual particles and matrix is a challenge. In this study, the main goal is to investigate the interphase of the epoxy/boehmite nanocomposites using AFM-based methods. We simplify the three-dimensional nanocomposite system to a two-dimensional horizontally layered sample with a large and easy to access interphase area. For this purpose, 1µm coatings of hydrothermally synthesized boehmite are prepared as the substrate on which the epoxy is later molded and cured. AFM surface potential and force maps were obtained on the cross-sectional cut of epoxy/ boehmite sample. The results show unexpectedly a large interphase area (approx. 1 µm) with different electrical and mechanical properties comparing to bulk epoxy. The average force-distance curves from this region showed more elastic behavior compared to bulk. The underlying mechanism of this influence is not fully understood yet. Thus, further investigation on the interphase region using the novel Nano-IR approach provides more information about the chemical characteristics. Numerical simulation will give complementary information to understand the effect of nanoparticles on the crosslinking density of the interphase. This can be different to bulk epoxy due to either different local temperature gradients or due to a surface selectivity of boehmite towards the monomer molecules. T2 - ICCS20–20th International Conference on Composite Structures CY - Paris, France DA - 04.09.2017 KW - AFM KW - AFM-IR KW - ImAFM KW - Boehmite KW - Epox KW - Nanocomposite KW - Interphase KW - Nanomechanics PY - 2017 AN - OPUS4-50689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frenzel, Florian T1 - Spectroscopic study of plasmon enhanced UPCON luminescence of silica-metal core-shell nanocomposites - status report N2 - The presentation focuses on the current state of the optical spectroscopic studies on plasmon enhanced upconversion luminescent processes of silica-metal core-shell nanocomposites. A general introduction of the upconversion process, the theoretical basis of plasmonic enhancement, the theoretical requirements in regard to NP architecture for plasmon enhanced UC will be outlined. The first proof-of-concept measurements show the difficulty in realization the theoretical measurement parameters in laboratory conditions and underline the need for shifting the experiments to single particle level.“ T2 - Gruppenseminar der Nanooptik an der HU Berlin, Prof. Benson, Institut für Physik, Raum 1‘404 CY - Berlin, Germany DA - 09.05.2017 KW - Upconversion KW - Pplasmon enhancement KW - Core-shell nanoparticles KW - Silca-metal nanoparticles PY - 2017 AN - OPUS4-50698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bienwald, Frank T1 - Optimierung der Aminosäureanalytik aromatischer Aminosäuren mittels HPLC N2 - Ausgehend von dem in der Literatur beschriebenen Verfahren zur Bestimmung aromatischer Aminosäuren konnte eine Analysemethode zur Proteinbestimmung über die optische Detektion von Tyrosin und Phenylalanin nach chromatographischer Trennung der Protein-Hydrolysate entwickelt werden, die gegenüber dem Verfahren aus der Literatur erhebliche Vorteile besitzt. Der Einsatz von Rundbodenvials stellt eine Neuerung und kostengünstige Alternative zu der konventionellen Hydrolyse in Vakuumhydrolyseröhrchen wie auch zu den Mikrowellenvials der Mikrowellenhydrolyse dar, die das Potential für Miniaturisierungen der Proben hat und sich zudem für große Probendurchsätze eignet. Anstelle der Mikrowellenheizungen wurde ein konventionelles Ölbad als Heizquelle verwendet. Somit ergibt sich eine Verbesserung auch darin, dass diese Methode geringere Geräteinvestitionen erfordert. Wie die Ergebnisse nahelegen, sind sowohl Salzsäure als auch Bromwasserstoffsäure geeignete Reagenzien, die bei der sauren Hydrolyse von Proteinen verwendet werden können. Mit Hilfe antioxidativer Zusätze können Nebenreaktionen erfolgreich vermieden werden. Hier haben sich L-Cystein und Oxalsäure als wirkungsvolle Additive herausgestellt. Wichtige Verbesserungen betreffen vor allem die Zeitersparnis bei der Hydrolyse, die Aufarbeitung der Hydrolysate und die chromatographischen Separationen. Erstere konnte gegenüber der konventionellen Methode von 22 Stunden auf 45 Minuten reduziert werden. Die chromatographische Trennung wurde so weit optimiert, dass die Laufzeit von 64 auf 35 Minuten verkürzt werden konnte. Zudem konnte auf das zeitraubende und kontaminationsanfällige Eindampfen der Hydrolysate verzichtet werden. Während der Aufarbeitung der Hydrolysate konnten die Menge eingesetzter Chemikalien reduziert und damit mögliche Störungen während der optischen Detektion verringert werden. Letztere wurde zum einen durch das Einbeziehen der UV-Absorption bei 260 nm erweitert, sodass eine Alternative zur Absorption bei 215 nm vorliegt, die ebenere Basislinien im Chromatogramm ermöglicht. Zum anderen wurde gezeigt, dass mit Hilfe der Fluoreszenz die Empfindlichkeit der Methode gegenüber der UV-Absorption erheblich verbessert werden kann. Anhand der Probe eines Birkenpollenextraktes ließ sich die Anwendbarkeit der optimierten Methode auf Realproben demonstrieren. KW - Aromatische Aminosäuren KW - Aromatic amino acid analysis KW - AAAA KW - Phenylalanine KW - Tyrosine KW - Hydrochloric acid KW - Hydrobromic acid KW - HCl KW - HBr KW - Chromatographie KW - Reversed-phase KW - Hydrolysis KW - AdvanceBio Peptide Map KW - PRP-C18 PY - 2017 SP - 1 EP - 71 PB - Humboldt-Universität zu Berlin CY - Berlin AN - OPUS4-54650 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Höhm, S. A1 - Kirner, Sabrina V. A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Laser-induced periodic surface structures — a scientific evergreen N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the availability of ultrashort laser pulses, LIPSS have gained an increasing attraction during the past decade, since these structures can be generated in a simple single-step process, which allows a surface nanostructuring for tailoring optical, mechanical, and chemical surface properties. In this study, the current state in the field of LIPSS is reviewed. Their formation mechanisms are analyzed in ultrafast time-resolved scattering, diffraction, and polarization constrained double-pulse experiments. These experiments allow us to address the question whether the LIPSS are seeded via ultrafast energy deposition mechanisms acting during the absorption of optical radiation or via self-organization after the irradiation process. Relevant control parameters of LIPSS are identified, and technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. KW - Laser ablation KW - Nanostructures KW - Surface functionalization KW - Surface texture KW - Laser-induced periodic surface structures (LIPSS) PY - 2017 DO - https://doi.org/10.1109/JSTQE.2016.2614183 SN - 1077-260X SN - 1558-4542 VL - 23 IS - 3 SP - 9000615 PB - IEEE AN - OPUS4-38633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero T1 - Force-distance curves on lubricant films: An approach to the characterization of the shape of the AFM tip N2 - Force-distance curves have been acquired with an atomic force microscope on perfluorpolyether films. It is shown that curves acquired on films of different thickness, at different rates and with different dwell times can be overlapped by rescaling the time or distance axis.When the time or distance axis is rescaled,the force depends only on the surface tension of perfluorpolyether and on geometrical properties of thetip (aperture and perimeter of the tip at a given distance from the apex). Hence, curves acquired with thesame tip overlap. By comparing curves acquired at different rates the dynamics of tip-wetting can be investigated. Fur-thermore, rescaled force-distance curves have been matched with the perimeter of cross sections ofthe tip, i.e. with the perimeter of the three-phase contact line. Such measurements pave the way for anon-destructive investigation of the tip shape. KW - Lubricant films KW - Surface tension KW - Atomic force microscopy KW - Force-distance curves KW - AFM tip shape PY - 2017 DO - https://doi.org/10.1016/j.micron.2016.11.006 SN - 0968-4328 VL - 93 SP - 20 EP - 28 AN - OPUS4-38391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rabe, Sebastian A1 - Schartel, Bernhard T1 - The rapid mass calorimeter: Understanding reduced-scale fire test results N2 - The effects of reducing specimen size on the fire behavior of polymeric materials were investigated by means of the rapid mass calorimeter, a high-throughput Screening instrument. Results from the rapid mass calorimeter were compared with those from the cone calorimeter. Correlation coefficients between the different measures of each method and between the two methods are discussed to elucidate the differences and similarities in the two methods. Materials with characteristic heat release rate (HRR) curves in the cone calorimeter were evaluated in detail. The rapid mass calorimeter produces valuable and interpretable results with HRR curve characteristics similar to cone calorimeter results. Compared to cone calorimeter measurements, material savings of 96% are achieved, while maintaining the Advantages of a macroscopic fire test. KW - Rapid mass calorimeter KW - High throughput KW - Cone calorimeter KW - Flame retardancy PY - 2017 DO - https://doi.org/10.1016/j.polymertesting.2016.11.027 SN - 0142-9418 VL - 57 SP - 165 EP - 174 PB - Elsevier AN - OPUS4-38739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ruhe, L. A1 - Ickert, Stefanie A1 - Hochkirch, U. A1 - Hofmann, J. A1 - Beck, S. A1 - Thomale, J. A1 - Linscheid, M. W. T1 - Comprehensive molecular characterization of a cisplatin-specific monoclonal antibody N2 - Despite their immense and rapidly increasing importance as analytical tools or therapeutic drugs, the detailed structural features of particular monoclonal antibodies are widely unknown. Here, an antibody already in use for diagnostic purposes and for molecular dosimetry studies in cancer therapy with very high affinity and specificity for cisplatin-induced DNA modifications was studied extensively. The molecular structure and modifications as well as the antigen specificity were investigated mainly by mass spectrometry. Using nano electrospray ionization mass spectrometry, it was possible to characterize the antibody in its native state. Tandem-MS experiments not only revealed specific fragments but also gave information on the molecular structure. The detailed primary structure was further elucidated by proteolytic treatment with a selection of enzymes and high resolution tandem-MS. The data were validated by comparison with known antibody sequences. Then, the complex glycan structures bound to the antibody were characterized in all detail. The Fc-bound oligosaccharides were released enzymatically and studied by matrix-assisted laser desorption/ionization mass spectrometry. Overall 16 different major glycan structures were identified. The binding specificity of the antibody was investigated by applying synthetic single and double stranded DNA oligomers harboring distinct Pt adducts. The antibody− antigen complexes were analyzed by mass spectrometry under native conditions. The stability of the complex with double stranded DNA was also investigated. KW - Antibody KW - Native MS KW - Cisplatin KW - PTM PY - 2017 DO - https://doi.org/10.1021/acs.molpharmaceut.7b00575 SN - 1543-8384 SN - 1543-8392 VL - 14 IS - 12 SP - 4454 EP - 4461 AN - OPUS4-43997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Zhiyang A1 - Merk, V. A1 - Müller, Anja A1 - Unger, Wolfgang A1 - Kneipp, Janina T1 - Role of metal cations in plasmon-catalyzed oxidation: A case study of p-aminothiophenol dimerization N2 - The mechanism of the plasmon-catalyzed reaction of p-aminothiophenol (PATP) to 4,4′-dimercaptoazobenzene (DMAB) on the surface of metal nanoparticles has been discussed using data from surface-enhanced Raman scattering of DMAB. Oxides and hydroxides formed in a plasmon-catalyzed process were proposed to play a central role in the reaction. Here, we report DMAB formation on gold nanoparticles occurring in the presence of the metal cations Ag+, Au3+, Pt4+, and Hg2+. The experiments were carried out under conditions where formation of gold oxide or hydroxide from the nanoparticles can be excluded and at high pH where the formation of the corresponding oxidic species from the metal ions is favored. On the basis of our results, we conclude that, under these conditions, the selective oxidation of PATP to DMAB takes place via formation of a metal oxide from the ionic species in a plasmon-catalyzed process. By evidencing the necessity of the presence of the metal cations, the reported results underpin the importance of metal oxides in the reaction. KW - Metal ions KW - Plasmonic catalysis KW - p-aminothiophenol KW - 4,4'-dimercaptoazobenzene KW - Surface-enhanced Raman scattering PY - 2017 UR - http://pubs.acs.org/doi/abs/10.1021/acscatal.7b02700 DO - https://doi.org/10.1021/acscatal.7b02700 SN - 2155-5435 N1 - Geburtsname von Müller, Anja: Hermanns, A. - Birth name of Müller, Anja: Hermanns, A. VL - 7 IS - 11 SP - 7803 EP - 7809 PB - American Chemical Society CY - Washington AN - OPUS4-43001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -