Substrate-Induced Orientational Order in the Isotropic Phase of Liquid Crystals

Abstract

Nematic order induced near a solid boundary in an otherwise isotropic liquid crystal is studied theoretically, at temperatures just above the bulk nematic-isotropic phase transition. Three distinct regimes are found, depending on the strength of orientational torques at the boundary: (i) strong orientational order, (ii) strong orientational order followed by a first-order transition to a state of weak orientational order as temperature is raised, and (iii) a state of weak orientational order.