RELATIONSHIP BETWEEN ALIGNMENT LAYER POLYMER SURFACE-STRUCTURES AND LIQUID-CRYSTAL DISPLAY PARAMETERS

The polar alignment layer (AL) surface provided relatively small liqui d crystal(LC) pretilt angles while polyimides with long alkyl side cha ins gave relatively large LC pretilt angles. The results suggest that LC pretilt angles, in addition to an anchoring effect, are greatly aff ected by both electronic and steric interactions between LC molecules and a polyimide alignment layer surface. Rubbing with a cotton cloth i nduces functional groups, side chains, and repeat units at, the surfac e of a liquid crystal polyimide AL to re-orient. It was discovered tha t rubbing induced polar functional groups and repeat units to re-orien t out-of-the-plane of the surface, and it made non-polar aliphatic sid e chains partially re-orient inwards, toward the bulk of the film.