Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 14: Complex Fluids

DY 14.5: Vortrag

Freitag, 4. März 2005, 16:30–16:45, TU H3010

Point force manipulation and activated dynamics of polymers adsorbed on structured substrates — •P. Kraikivski, R. Lipowsky, and J. Kierfeld — MPI für Kolloid- und Grenzflächenforschung, 14424 Potsdam

We study the activated motion of adsorbed polymers which are driven over a structured substrate by applying a localized point force. Our theory applies to experiments on single adsorbed polymers using, for example, force microscopy tips to drive the polymer. We consider both flexible and semiflexible polymers, and the surface structure is represented by double-well or periodic potentials. The dynamics is governed by kink-like excitations for which we calculate shapes, energies, and critical point forces. Thermally activated motion proceeds by the nucleation of a kink-antikink pair at the point where the force is applied and subsequent diffusive separation of kink and antikink. In the stationary state of the driven polymer the collective kink dynamics can be described by an one-dimensional symmetric simple exclusion process.