Theory of translational diffusion in the nematic phase

摘要

A model of translational diffusion in the nematic phase is proposed. The generalized free volume approach is used to evaluate the diffusion coefficient of a small hard-sphere tracer among monodisperse rodlike particles interacting via the Warner nematic potential. The free volume of the sample is visualized as a system of rigid tubelike shells polydisperse in length (a Cohen-Turnbull distribution) dissolved in the rodlike matrix. The equilibrium orientational distribution function of shells is found by means of the Flory lattice method. The theory is specialized to typical nematogens and is critically compared with experimental results.