TY - JOUR A1 - Wäsche, Rolf A1 - Hartelt, Manfred A1 - Cappella, Brunero T1 - The use of AFM for high resolution imaging of macroscopic wear scars N2 - In this article we demonstrate the use of atomic force microscopy (AFM) measurements for the study of macroscopic wear scars. By stitching AFM images acquired over the wear scar, the detailed structure of the scar can be characterized even when the scar is much wider than the typical maximum scan range of the AFM (50–100 µm). The results obtained by AFM are compared with those yielded by white light interferometry (WLI). The comparison validates the WLI measurements; at the same time, it shows decisive differences in the resolutions of these two methods. As a consequence, AFM measurements are necessary whenever a precise characterization of the structure of the scar is required. However, since stitching of AFM images is rather time-consuming, white light interferometry is recommended as a faster method whenever experiments are aimed at just a gross characterization of the scar and the measurement of mean quantities (e.g. the wear volume). KW - Wear scar KW - Imaging KW - Roughness KW - Wear volume KW - Atomic force microscopy KW - White light interferometry PY - 2014 U6 - https://doi.org/10.1016/j.wear.2013.11.009 SN - 0043-1648 VL - 309 IS - 1-2 SP - 120 EP - 125 PB - Elsevier CY - Amsterdam AN - OPUS4-30289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krämer, Günther A1 - Griepentrog, Michael A1 - Bonaccurso, E. A1 - Cappella, Brunero T1 - Study of morphology and mechanical properties of polystyrene-polybutadiene blends with nanometre resolution using AFM and force-distance curves N2 - Thin polybutadiene/polystyrene blend films were deposited on glass substrates by spin-coating. The two polymers were chosen, as they are immiscible and differ strongly in their mechanical properties. The blend was characterized with Tapping Mode and force–distance curves. Several advantages of force–distance curves measurements compared to Tapping Mode are shown, most of all the capability of yielding quantitative information about several properties, such as Young's modulus and adhesion. Also the aging behaviour of the blend exposed to air could be observed, in particular the increase of the Young's modulus due to cross-linking and dewetting processes. Additionally, the sample was used to improve the resolution of force–distance curves up to 6 nm, which is to date the best resolution achieved with force–distance curves. Such an improvement resolves the major disadvantage of force–distance curves, compared to other scanning mode, i.e. its inferior resolution. KW - Polymer blends KW - Mechanical properties KW - Atomic force microscopy KW - Force-distance curves KW - High-resolution force-volume PY - 2014 U6 - https://doi.org/10.1016/j.eurpolymj.2014.03.026 SN - 0014-3057 SN - 1873-1945 VL - 55 SP - 123 EP - 134 PB - Elsevier CY - Oxford AN - OPUS4-30625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Wassenberg, J. R. A1 - Heim, L.-O. A1 - Klostermann, M. A1 - Venzmer, J. A1 - Bonaccurso, E. T1 - Mechanical properties of silicone methacrylate microparticles determined by AFM colloidal probe technique N2 - The mechanical properties of seven types of silicone methacrylate microparticles prepared by solution polymerization with a Pickering emulsifier were investigated by Atomic Force Microscope force–displacement curves acquired in air with the Colloidal Probe Technique, i.e., with spherical SiO2 particles of known radius glued on tipless cantilevers. The deformation curves derived from the force–displacement curves were fitted with Hertz equation for the contact between two spherical particles, which lead to the determination of the elastic modulus of the samples. The performed measurements and the analysis provide quite exact values of the elastic modulus of all investigated polymer particles. Moreover, the results of the measurements were repeatable over large time intervals, also with different experimental setups. The influence of the sample preparation (polymerization method, cross-linking density of the polymer, and thickness of the external shell of the Pickering emulsifier) is discussed as well. The elastic moduli correlate with the cross-linking density (from 2 MPa for low cross-linking density up to 100–130 MPa for medium cross-linking density), whereas the thickness of the external shell formed by the Pickering emulsifier has no measurable influence on the mechanical properties of the microparticles. KW - Colloidal probe technique KW - Hertz model KW - Silicone elastomer PY - 2014 U6 - https://doi.org/10.1016/j.polymer.2014.01.021 SN - 0032-3861 SN - 1873-2291 VL - 55 IS - 5 SP - 1209 EP - 1216 PB - Elsevier Ltd. AN - OPUS4-30316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cappella, Brunero T1 - Mechanical properties of homogeneous and microstructured polymer films T2 - Institut für Physikalische und Theoretische Chemie der Universität Siegen CY - Siegen, Germany DA - 2014-06-23 PY - 2014 AN - OPUS4-32026 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -