Graphene oxide hydrogen bonding liquid crystals using carboxylic acids as proton donors: Liquid-crystalline behavior and ferroelectric property

A series of cholesterol-based graphene oxide liquid crystals (GOLCs) were synthesized in a hydrogen bond self-assembly process by use of graphene oxide, a chiral liquid crystal cholesteryl piperidine-2-carboxylate and a crosslinking liquid crystal [1,1′-biphenyl]-4,4′-diyl bis(6-methoxynicotinate). The chemical structure, liquid-crystalline behavior and ferroelectric property of the GOLCs were investigated by various scientific instruments and methods, and the effects of different liquid crystal constituent content on the liquid-crystalline behavior and ferroelectric property were investigated. All the GOLCs showed chiral smectic C phase. The temperature of melting point and mesophase-isotropic phase transition increased with the decrease of chiral liquid crystal content and the increase of crosslinking liquid crystal content for these GOLCs. With the increasing concentration of chiral liquid crystal compounds in the GOLCs, the ferroelectric parameters including saturation polarization and remanent polarization initially exhibited an upward trend before subsequently declining. This phenomenon can be attributed to the varied chiral, rigid, and polar characteristics of the different liquid crystal compounds. These GOLCs demonstrated the highest saturation polarization and remanent polarization values reaching 0.6 and 0.3 μC/cm 2 , respectively, which indicates superior ferroelectric performance.