ALIGNMENT PHOTOREGULATION OF A NEMATIC LIQUID CRYSTAL BY SURFACE ADSORPTION OF AMINOALKYLATED AZOBENZENES

Adsorption behavior of azobenzenes having an aminoalkyl residue onto a silica surface is described. Immersion of a silica plate in a benzene solution of an aminoalkylated azobenzene resulted in efficient adsorption to form face-to-face aggregates which are converted into monomeric states by partial desorption. Silica plates adsorbing the azobenzene bearing an aminoalkyl residue were employed to achieve the surface-assisted photoregulation of alignment of a nematic liquid crystal between homeotropic and planar modes. Based on these observations, a convenient method to prepare command surfaces for the orientational photoregulation of liquid crystals was presented by filling a liquid crystal containing an aminoalkylated azobenzene into an empty cell composed of clear silica plates.