Relationship between Surface Order and Surface Azimuthal Anchoring Strength on Polyimide with Linearly Polarized Ultraviolet Light Exposure

Abstract

The liquid crystal (LC) molecular order near the polyimide surface with linearly polarized ultraviolet (LPUV) light exposure is re-examined by the improved torque balance method. The surface azimuthal anchoring strength measured by the improved torque balance method is larger than that measured by the conventional torque balance method and is considered to be significantly affected by the phase transition behavior. On the basis of this result, it can be argued that the correlation between the LPUV light dosage and the surface azimuthal anchoring strength should be improved in considering of the surface order mechanism. The absolute surface azimuthal anchoring strength is investigated with respect to the phase transition characteristics. Photoalignment revealed that a relatively strong surface azimuthal anchoring strength may be obtained. Furthermore, the effects of photoalignment and rubbing of different alignment processes were examined.