2-naphthoxymethyl-substituted Polystyrenes for homeotropic liquid-crystal alignment layers

Abstract

A series of 2-naphthoxymethyl-substituted polystyrenes (P2NAP) were prepared by the reaction of poly(chloromethylstyrene) with different amounts of 2-naphthol to investigate the liquid-crystal (LC) alignment properties of these polymer films. P2NAP with only 2-naphthoxymethyl side groups (100% conversion of chloromethyl to 2-naphthoxymethyl) was obtained when 180 mol-% of naphthol was used in the reaction at 80 degrees C for 12 h. LC cells fabricated with unrubbed P2NAP films exhibited a homeotropic LC alignment behavior with a pre-title angle of approximately 90 degrees. The homeotropic LC alignment behavior of the unrubbed LC cell of the P2NAP film was ascribed to the head-on type incorporation of a nonpolar bulky 2-naphthoxy-methyl group into the phenyl side group of the polystyrene.