Eur. Phys. J. E (2011) 34: 109
https://doi.org/10.1140/epje/i2011-11109-5

Regular Article

Order parameter dependence of the viscosity coefficients of a biaxial nematic liquid crystal

Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, G1 1XH, Glasgow, Scotland, UK

^* e-mail: andre.sonnet@strath.ac.uk

Received: 23 February 2011
Revised: 14 July 2011
Accepted: 29 August 2011
Published online: 11 October 2011

Abstract

We derive expressions for the order parameter dependence of the viscosity coefficients of a biaxial nematic liquid crystal by comparing its dissipation function expressed in terms of directors with that expressed in terms of order tensors. The results enable us to identify the dominant flow viscosity coefficients and to compare their temperature variation according to their dependence on the dominant scalar order parameters. By considering different orientations of an external field, we identify three characteristic switching times corresponding to three rotational viscosities, and we estimate the ratio of the switching times of the primary and the secondary directors.