Point force manipulation and activated dynamics of polymers adsorbed on structured substratesP. Kraikivski, R. Lipowsky and J. Kierfeld
Max-Planck-Institut für Kolloid- und Grenzflächenforschung 14424 Potsdam, Germany
received 22 February 2005; accepted in final form 2 May 2005
published online 20 May 2005
We study the activated motion of adsorbed polymers which are driven over a structured substrate by a localized point force. Our theory applies to experiments with single polymers using, for example, tips of scanning force microscopes to drag the polymer. We consider both flexible and semiflexible polymers, and the lateral 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 a one-dimensional symmetric simple exclusion process.
82.35.Gh - Polymers on surfaces; adhesion.
87.15.-v - Biomolecules: structure and physical properties.
87.15.He - Dynamics and conformational changes.
© EDP Sciences 2005