Relationship between rubbing‐induced anisotropy and surface azimuthal anchoring energy of nematic liquid crystals

Abstract

The relationship between the rubbing-induced anisotropy of alignment films and the surface azimuthal anchoring energy of nematic liquid crystals was investigated using three kinds of rubbing cloths. Reflection ellipsometry revealed that the optical surface anisotropy of polyimide alignment films increases monotonically with increasing RS. The surface azimuthal anchoring energy measured by the torque balance method depends on the rubbing-induced anisotropy of alignment films. This indicates that liquid crystal molecular alignment can be controlled by monitoring the rubbing-induced optical anisotropy of alignment films when a suitable rubbing cloth is used.

Self-Consistent Explanation of the Untwist Alignment of Ferroelectric Nematic Liquid Crystals with Decreasing Cell Thickness and Deviation of the Surface Easy Axis Experimented upon Using the Brewster Angle Reflection Method

“…The resultant L ranges from 500 to 3000 mm. As a reference, the azimuthal anchoring energy of polyimide combined with the cyanide nematic mixture ZLI-2293 (Merck) showed a gradual rubbing strength dependence on the order of 10 −4 J/m 2 [29], and the pretilt angle was less than 2 degrees. Sandwich-type cells were created by arranging two substrates with their rubbed polyimide surfaces facing inward such that their rubbing directions were anti-parallel to each other to promote planar alignment of the NLC.…”