Gelation of Liquid Crystal Compounds Having a Coumarin Skeleton

Abstract

2H-Chromen-2-one-6-yl 4-alkoxybenzoates(1) and 4-alkoxybiphenyl 4'-calboxylates(2) were synthesized and the LC properties and the gelation abilities were examined. Compounds 1 and 2 reveal smectic A and/or nematic phases, and gelatinize various organic solvents such as cyclohexane, 1-octanol, and acetonitrile. The transition between the gel phase and the isotropic fluid is thermally reversible. The images of gel observed with SEM show fine fibers and small pores which are considered to be occupied with organic solvents. The polar effect of the terminal lactone group and/or solvophobic one between organic solvent and molecule are supposed to play important role for gelation.