Phase behavior of liquid-crystalline copolymer/liquid crystal blends

Thermodynamic phase behavior was studied for blends between side-chain liquid-crystalline (SCLC) copolymers and a low molecular weight liquid crystal (LC). SCLC copolymers, Copolyx having x mol fraction of a benzoic acid unit and 1−x mol fraction of a cyanobiphenyl group in their side chain, were prepared by radical polymerization and mixed with a low molecular weight LC, 4-cyano-4′-n-hexyloxybiphenyl (6OCB). The phase diagram of the Copoly0.24/6OCB blend exhibited an upper critical solution temperature which was not observed for homopolymer systems. Employing SCLC copolymers having two different kinds of mesogens in polymer/low molecular weight LC blends enabled us to obtain the new type of phase diagram.