Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Dynamik und Statistische Physik
DY 35: Ferro Fluids / Liquid Chrystals
DY 35.7: Vortrag
Mittwoch, 29. März 2006, 16:00–16:15, SCH 251
The influence of shear rate fluctuations on the orientational dynamics — •Sebastian Heidenreich1, Patrick Ilg1,2, and Siegfried Hess1 — 1Institut für Theoretische Physik, Technische Universität Berlin, D-10623, Germany — 2Department de Physique des Materiaux, UCB Lyon1, F-69622 Villeurbanne, France
The flow behavior of liquid crystals is strongly affected by the coupling between the flow and the molecular orientation. Nematic liquid crystals which respond with a time-dependent orientational behavior can be rather complex. A relatively simple model based on a nonlinear equation for the second rank alignment tensor which can be derived form irreversible thermodynamics [1-3]. Here we investigate the influence of fluctuating shear rates on the orientational dynamics in the case of spatially homogeneous and spatially inhomogeneous alignment. We found that uncorrelated fluctuations of the shear rate in general have little effect on the orientational dynamics of nematics, whereas the effect of correlated fluctuation is more significant. Further we present a new amended potential modeling the isotropic-to-nematic transition. In contrary to the Landau-de Gennes potential our potential has the advantage to restrict the order parameter to physically admissible values.
[1] S. Hess,Z. Naturforsch. 30a, 728 (1975), 31a 1507 (1976). [2] P. D. Olmsted and P. Goldbart,Phys. Rev. A 41, 4578 (1990); Phys. Rev. A 46,4966 (1992). [3] C. Pereira Borgmeyer and S. Hess, J. Non-Equilib. Thermodyn. 20, 359 (1995).