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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Transport and Confinement I
CPP 17.5: Talk
Tuesday, April 1, 2014, 10:45–11:00, ZEU 260
Hydrodynamic interactions induce anomalous diffusion under partial confinement — •Johannes Bleibel1,2, Alvaro Dominguez3, and Martin Oettel1 — 1Institut für angewandte Physik, Universität Tübingen, Tübingen, Germany — 2Max-Planck-Institut für intelligente Systeme, Stuttgart, Germany — 3Física Teórica, Universidad de Sevilla, Sevilla, Spain
We consider a system of colloidal particles which are restricted to a plane, but surrounded by an unbound fluid. Examples for such a setup are colloids trapped at fluid-fluid interfaces or colloids trapped by laser fields. Although this partial confinement allows for motion of the particles only within the plane, their dynamics is influenced by hydrodynamic interactions mediated by the unconfined, three–dimensional flow of the embedding fluid. We demonstrate that this dimensionality mismatch induces a characteristic divergence in the collective diffusion coefficient of the colloidal subsystem. This result, independent of the specific interparticle forces in the monolayer, is solely due to the kinematical constraint on the colloidal particles, and it is different from the known divergence of transport coefficients in purely one or two–dimensional fluids. We study the consequences for two different setups: We find anomalous diffusion for an ideal–gas–like system of non–interacting colloidal particles and a significant speedup for the capillary induced collapse of a colloidal patch at a fluid interface.