Director orientation of a ferroelectric liquid crystal on substrates with rubbing treatment: The effect of surface anchoring strength

One of the most important problems with ferroelectric liquid crystals is obtaining homogeneous as well as bistable alignment, not only to study their physical characteristics but also for their application to optical devices. In this connection it was predicted that the formation of homogeneous alignment requires strong surface anchoring, whereas bistability requires weak anchoring. We have therefore developed a method to determine the surface anchoring strength, and have tried to clarify whether there is a suitable anchoring range. It was found that A/K₂₂ (A is the surface anchoring and K₂₂ is the twist elastic constant of liquid crystal) of 4 × 10^-2 to 2 μm^-1 satisfies the contradictory requirements for homogeneous as well as bistable alignments for the material studied, and the bookshelf structure is successfully formed with this condition.