Correlation between surface orientation of liquid crystal monolayer and pretilt angle in liquid crystal cells

Abstract

We determined the orientational distribution function of the liquid crystal(LC) monolayer on rubbed polyimide films by optical second harmonic generation(SHG) and investigated the correlation between the surface LC orientation and the pretilt angle in LC cells. The LC samples used were a homologous series of 4'-n-alkyl-4-cyanobiphenyl (nCB; n=5-8). The pretilt angles were observed as a function of rubbing strength for nCB. The dependence of pretilt angle was classified into two types according to the number of carbon atom in alkyl chain.