Physical Gelation of Nematic Liquid Crystals with Amino Acid Derivatives Leading to the Formation of Soft Solids Responsive to Electric Field.

Abstract

4′-heptyloxybiphenyl (7OCB), have been physically gelled due to the formation of hydrogen-bonded networks comprised of amino acid derivatives. The mixtures of nematic liquid crystals and amino acid derivatives exhibit thermoreversible three states, isotropic, isotropic gel, and nematic liquid-crystalline gel, through the phase change of each of components. The gel states are induced by the formation of microphase-separated structures and transition properties of liquid-crystalline solvents in the network structures are maintained. The anisotropic gels of 5CHB can respond to electric fields in polyimide-coated liquid crystal cells. The existence of a small amount of gelling agents has great effects on the electro-optic properties. Acceleration of response behavior of the nematic liquid crystal has been achieved by such physical gelation.