Liquid Crystal Alignment Properties on Crosslinkable Polymer Films with Plasma Surface Modification

ABSTRACT

The plasma surface modification is carried out on a polymer film, and the surface is subsequently rubbed. The side chains of the polymer are crosslinked in the plasma process. Liquid crystal molecules uniformly align perpendicular to the rubbing direction on the unmodified surface and parallel on the modified surface. The dichroism of the polarized UV absorption to the rubbing direction is positive in the modified film as compared to the negative dichroism in the unmodified film. The sign of the dichroism is reasonable to explain easy axes of modified and unmodified film surface.

Keywords:

• alignment patterning
• crosslinkable polymer
• easy axis
• plasma surface modification
• rubbing treatment