Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Poster II

DY 30.65: Poster

Thursday, March 29, 2007, 16:00–18:00, Poster D

Transport Behavior of Colloids in Micro-Channels — •Peter Henseler and Peter Nielaba — Fachbereich Physik, Universität Konstanz, D-78457 Konstanz

The transport behavior of a system of gravitationally driven colloidal particles is investigated. The particle interactions are determined by the superparamagnetic behavior of the particles. They can thus be arranged in a hexagonal order by application of an external magnetic field. Therefore the motion of the particles through a narrow channel is governed by this positioning and a layered structure forms parallel to the walls. The arrangement of the particles is perturbed by diffusion and the motion induced by gravity. Due to these combined influences a density gradient forms along the direction of motion of the particles. A reconfiguration of the ordered structure is observed leading to a reduction of the number of layers. Experiments and Brownian dynamics (BD) simulations show that this is due to the density gradient along the channel. Furthermore we present simulation results for various channel geometries and the effect of obstacles within the channel.

[1] M. Köppl, P. Henseler, A. Erbe, P. Nielaba and P. Leiderer, Phys. Rev. Lett. 97, 208302 (2006)