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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.113: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Dynamic dielectric polarization of tumbling nematic liquid crystals — •Stefan Grandner, Sebastian Heidenreich, Sabine Klapp, and Siegfried Hess — Institut für theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

The orientation of a tumbling nematic liquid crystal shows a time dependent response in a stationary Couette flow. This behavior can be described by a nonlinear inhomogeneous relaxation equation for the alignment tensor [1]. Different types of periodic behavior referred to as tumbling, wagging, kayaking tumbling and kayaking wagging have been identified. Even chaotic solutions are found [2]. Here, we consider a liquid crystal consisting of particles with an electric dipole moment. The coupling between the alignment tensor and the electric polarization is taken into account in an extended Landau-de Gennes potential. The microscopic origin of these terms is analysed. The resulting dynamic equations are solved and the physical consequences for the time dependence of the electric polarization of a streaming tumbling nematic are discussed.
S. Hess, Z. Naturforsch. 30a, 728, 1224 (1975)
G. Rienäcker, M. Kröger and S. Hess, Phys. Rev. E 66, 040702(R) (2002)