Alignment of Liquid Crystals by Grooved Surfaces

Abstract

Abstract We have observed alignment of nematic, cholesteric and smectic liquid crystals in directions depending on the orientation of submicroscopic, parallel grooves in adjacent glass and fused quartz surfaces. The alignment can be explained on the basis of elastic strain energy in the bulk of the liquid crystal that would be increased if the long axes of the molecules were aligned by the surface but were not approximately parallel to the groove direction. We have also observed alignment parallel to grooved surfaces but skewed with respect to the grooves, apparently when long molecules become attached to the surface in a direction that causes a competing torque on the director of adjacent liquid crystal molecules.