Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 55: Poster: Noneq. Stat. Phys., Stat. Bio. Phys., Brownian

DY 55.7: Poster

Thursday, April 4, 2019, 15:00–18:00, Poster B2

Dynamic ordering of driven spherocylinders in a non-equilibrium suspension of small colloidal spheres — •Anton Lüders, Ullrich Siems, and Peter Nielaba — Department of Physics, University of Konstanz, 78457 Konstanz, Germany

The ordering effects of driven spherocylinder-shaped rods in a colloidal suspension of small spheres confined to a two-dimensional channel geometry are observed via Brownian Dynamics simulations without hydrodynamics. To describe the ordering, an order parameter and an expression for a potential of mean force of an equivalent equilibrium system are defined and analyzed. By varying the application point of the external force along the rods and thus the resulting lever, a transition from a preferred orientation parallel to the direction of the force to a preferred orientation perpendicular to the direction of the force was observed. It is shown that this effect can only be found, if the spheres and multiple rods are present. Furthermore, a dependency of the order parameter on the absolute value of the force was discovered. The analysis of the potential of mean force further indicates a transition between two different phases of mean orientation. The observation of the flow equilibrium mean velocity in channel direction led to a s-shaped progression regarding the lever dependency, also marking a transition between two states linked to the mean orientation of the rods. By means of a finite size analysis it was possible to show that the transition between the two orientation states is a general phenomenon of the observed rod-sphere mixture.