SUBSURFACE DEFORMATIONS IN NEMATIC LIQUID-CRYSTALS

The existence of subsurface deformations in a nematic liquid crystal s ample of finite thickness is considered from a molecular point of view . A lattice approximation is used to take into account the intermolecu lar interactions responsible for the nematic phase. The analysis shows that for the Maier-Saupe interaction law the director profile is a sm ooth function in the whole sample. In contrast, in the framework of ou r simple model, for the induced-dipole-induced-dipole interaction law the director profile presents a large subsurface deformation. The resu lts of our calculation are compared with the elastic theories for nema tic liquid crystals recently proposed. In particular it is shown that the intermolecular interactions responsible for the effective splay-be nd elastic constant are the origin for the Subsurface discontinuity in pretilted nematic liquid crystal samples. Our predictions are obvious ly limited by the applicability of the naive model considered in the p resent analysis.