Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: SYMPOSIUM Driven Soft Matter II

CPP 17.5: Vortrag

Dienstag, 26. Februar 2008, 15:30–15:45, C 130

Entangled Dynamics of a Stiff Polymer — •Thomas Franosch, Felix Höfling, Tobias Munk, and Erwin Frey — Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 München, Germany

Entangled networks of stiff biopolymers exhibit complex response, emerging from the topological constraints that neighboring filaments impose upon each other. The relevant dynamic processes cover many decades in time, posing a tremendous challenge both to experiments and simulations. Pioneered by Edwards and de Gennes, the many-filament interaction was condensed in the picture of reptation in a confining tube. To achieve progress beyond simple scaling arguments, we propose a class of reference models for entanglement dynamics that allows us to provide a quantitative foundation of the tube concept for stiff polymers. For the fundamental limiting case of an infinitely thin needle exploring a planar parcours of point obstacles, we have performed large-scale simulations. Our results unambiguously prove the conjectured scaling from the fast transverse equilibration to the slowest process of orientational relaxation. In the highly entangled regime, the slow dynamics becomes attainable by employing a novel simulation algorithm based on interval analysis. We determine the rotational diffusion coefficient of the tracer, its angular confinement and the tube diameter. In addition, the tube concept is extended to a theoretical description of the complete orientational dynamics including a two-step relaxation, which is corroborated by our simulation results.