Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Fachverband Dynamik und Statistische Physik
DY 30: Poster II
DY 30.59: Poster
Donnerstag, 29. März 2007, 16:00–18:00, Poster D
Magnetic fields generated in dipolar nematic liquid crystals under shear — •S. Grandner1, S. Heidenreich1, P. Ilg1,2, S.H.L. Klapp1,3, and S. Hess1 — 1Institute for Theoretical Physics, TU Berlin, 10623 Berlin, Germany — 2Institute for Polymers, ETH Zürich, 8093 Zürich, Switzerland — 3Stranski-Laboratorium for Physical and Theoretical Chemistry, TU Berlin, 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 transport equation for the alignment tensor [1]. Here, we generalize this approach to investigate a liquid crystal consisting of particles with an electric dipole moment [2]. The coupling between the alignment tensor and the electric polarisation is taken into account via an extended Landau-de Gennes potential. For certain ranges of the coupling parameter one can find a macroscopic electric polarisation in the nematic state without shear. The dynamic equations in the presence of shear are solved revealing complex dynamic behavior characterized by different states such as tumbling, wagging or chaotic [3]. According to the inhomogeneous Maxwell equation the time dependence of the electric polarisation yields a magnetic field, which is of measurable strength.
[1] S. Hess, Z. Naturforsch. 30a, 728, 1224 (1975)
[2] S. Grandner, S. Heidenreich, P. Ilg, S.H.L. Klapp and S. Hess - Dynamic electric polarization of nematic liquid crystals subjected to a shear flow (submitted)
[3] G. Rienäcker, M. Kröger and S. Hess, Phys. Rev. E 66, 040702(R) (2002)