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CPP: Chemische Physik und Polymerphysik
CPP 28: Biological Systems
CPP 28.8: Vortrag
Freitag, 31. März 2006, 12:15–12:30, ZEU Lich
Nanofriction: Pulling polymers along surfaces — •Andreas Serr1,2 and Roland R. Netz1 — 1Physik Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany — 2serr@ph.tum.de
Over the last decade the method of AFM force spectroscopy has been used to extract single polymer data, e.g. on protein unfolding dynamics, polymer elasticity, covalent bond breaking and adsorption strengths. When pulling on polymers physisorbed to surfaces, a transition from stick to slip has been noted by change of pH, ionic strength or solvent conditions, which is yet not understood. Using a simple, parameterized model for polymer-surface interactions we predict the lateral and vertical forces for both pulling the polymer off from the surface and for pulling laterally alongside the surface [1]. In principle, the friction coefficient can be extracted from such experiments and its dependence on polymer & surface type, pH, etc. could be mapped out. Microscopic models and simulations provide insight into the fundamental dissipation processes for different types of polymer-surface interactions.
[1] A. Serr, R. R. Netz, Pulling adsorbed polymers from surfaces with the AFM: stick versus slip, peeling versus gliding, submitted to Europhys. Lett., 2005.