Molecular Orientation of Liquid Crystal Thin Films on Rubbed Polymer Surface Studied by Near Edge X-ray Absorption Fine Structure

Abstract

On a rubbed polymer substrate, liquid crystal (LC) molecules can be aligned in parallel to the rubbing direction. In this paper, we report a clear evidence of LC molecular orientation studied by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The incident-angle dependence of the resonance intensity of the C-K and N-K to pi*-states in CC double bonds and CN triple bonds is explained by molecular orientation of 5CB (4-pentyl-4'-cyanobiphenyl) on the rubbed substrate of PMDA-ODA.