TY - JOUR A1 - Dmitriev, A. I. A1 - Österle, Werner A1 - Kloß, Heinz A1 - Orts-Gil, Guillermo T1 - A study of third body behaviour under dry sliding conditions. Comparison of nanoscale modelling with experiment N2 - Automotive brake pads consist of many components but it is still not entirely clear which role each of the elements of this complex composition plays to provide the specified regimes of sliding. This is due to the mutual interaction of multiscale mechanisms, realized during the friction. In this work we have attempted to partly answer this question using computer simulations. Since the simulation allows us to consider various combinations of the structure of the system being simulated ceteris paribus, it becomes possible to understand the role of each constituent sequentially. The main attention is paid to the structure and composition of the thin film that forms on the surface of both bodies as a result of compaction of the wear product, its chemical composition and oxidation. This layer, also named a third body or friction film, differs in composition and microstructure from the two first bodies. We considered a single contact for the steady state sliding when the structure and composition of friction films already are formed. As a modelling tool we used the method of movable cellular automata, which has well proven itself in solving of such tasks. We investigated the influence of modification of the structure and composition of the third body on the features of system behaviour at friction. To assess the adequacy of the numerical model, experimental studies with an artificial third body were also carried out. The Simulation results are in good agreement with experimental data. KW - Third body KW - Dry sliding KW - Mechanically mixed layer KW - Computer simulation PY - 2012 U6 - https://doi.org/10.3176/eng.2012.3.12 SN - 1736-6038 SN - 1736-7522 VL - 18 IS - 3 SP - 270 EP - 278 AN - OPUS4-38545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natte, Kishore A1 - Friedrich, Jörg Florian A1 - Wohlrab, Sebastian A1 - Lutzki, J. A1 - von Klitzing, R. A1 - Österle, Werner A1 - Orts-Gil, Guillermo T1 - Impact of polymer shell on the formation and time evolution of nanoparticle-protein corona N2 - The study of protein corona formation on nanoparticles (NPs) represents an actual main issue in colloidal, biomedical and toxicological sciences. However, little is known about the influence of polymer shells on the formation and time evolution of protein corona onto functionalized NPs. Therefore, silicapoly(ethylene glycol) core–shell nanohybrids (SNPs@PEG) with different polymer molecular weights (MW) were synthesized and exhaustively characterized. Bovine serum albumin (BSA) at different concentrations (0.1–6 wt%) was used as model protein to study protein corona formation and time evolution. For pristine SNPs and SNPs@PEG (MW = 350 g/mol), zeta potential at different incubation times show a dynamical evolution of the nanoparticle–protein corona. Oppositely, for SNPs@PEG with MW ≥2000 g/mol a significant suppression of corona formation and time evolution was observed. Furthermore, AFM investigations suggest a different orientation (side-chain or perpendicular) and Penetration depth of BSA toward PEGylated surfaces depending on the polymer length which may explain differences in protein corona evolution. KW - Nanoparticles KW - Silica KW - PEGylation KW - Protein corona KW - BSA KW - Biointerface PY - 2013 U6 - https://doi.org/10.1016/j.colsurfb.2012.11.019 SN - 0927-7765 VL - 104 SP - 213 EP - 220 PB - Elsevier AN - OPUS4-38547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natte, Kishore A1 - Österle, Werner A1 - Friedrich, Jörg Florian A1 - von Klitzing, R. A1 - Orts-Gil, Guillermo T1 - Tuning interfacial properties and colloidal behavior of hybrid nanoparticles by controlling the polymer precursor N2 - A facile and versatile synthetic route for controlling the size and surface potential of organic–inorganic hybrid silica nanoparticles (NPs) is introduced in this paper. For polymer-grafted NPs, the density of polymer chains on the surface is strongly affected by the concentration of precursor. Nevertheless, for condensed NPs, the precursor concentration determines the particle size but not the density of polymer chains on the surface or the adsorption of bovine serum albumin (BSA). Results presented here may have Major implications in biomedical and colloidal chemistry since interfacial and colloidal properties are known to drive several processes associated with nanoparticles in biological media. KW - BSA KW - Bio-interface KW - Nanosilica hybrids KW - PEG KW - Protein corona PY - 2012 U6 - https://doi.org/10.1002/macp.201200148 SN - 0025-116X SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2412 EP - 2419 PB - Whiley-VCH CY - Weinheim AN - OPUS4-38549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -