Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Micro and Nano Fluidics II: Slipping + soft objects in flow

CPP 27.6: Talk

Thursday, February 28, 2008, 15:15–15:30, C 264

Long ranged hydrodynamic repulsion of polymers at interfaces — •Christian Sendner and Roland Netz — Physik Department, Technische Universität München

We consider the influence of a no slip boundary on polymers in external fields or shear flow in the zero Reynolds number regime. Due to the interplay between thermal fluctuations and hydrodynamic interactions, which leads to a preferred orientation of the polymer with respect to the surface, polymers are repelled from the interface with a force that decays with the inverse square of the surface separation. On the basis of a Fokker-Planck analysis, we give scaling relations for this repulsion in terms of length of the polymer, shear strength or external force and temperature. Brownian Dynamic simulations including hydrodynamic interactions confirm these scaling laws. This repulsive force can be used in microfluidic applications to control adsorption and desorption of polymers.