Microscopic Theory of Flow Alignment in Nematic Liquid Crystals

Abstract

A microscopic theory of the flow alignment in nematic liquid crystals is presented. The calculation is based on a thermodynamic sum rule derived earlier. The temperature dependence of the flow-alignment angle is obtained in terms of the nematic order parameter $S(T)$. The theory favors stable flow alignment, but the orientational instability found by G\"ahwiller cannot be ruled out.