LANDAU-DEGENNES THEORY OF ANCHORING TRANSITIONS AT A NEMATIC LIQUID-CRYSTAL SUBSTRATE INTERFACE

We have used Landau-de Gennes theory to study anchoring and anchoring transitions at the interface between a nematic liquid crystal and a smooth solid substrate. In contrast to earlier work by Sen and Sullivan, we allow for a spatially varying tilt angle and solve the Euler-Lagrange equations requiring that the order parameters be uniform far from the wall. We have found that temperature-driven anchoring transitions akin to those observed experimentally can be obtained either as a result of the change in the surface order parameter or due to competition between the ordering effects of the solid surface and the nascent isotropic-nematic interface as T(NI) is approached, in the regime of complete wetting by the isotropic phase. Predictions have also been made for the experimentally observable values of the anchoring energy.