A STUDY OF THE PHASE-BEHAVIOR OF BLENDS OF SIDE-CHAIN LIQUID-CRYSTAL POLYMERS

The phase behaviour of mixtures of acrylate based side-chain liquid crystal polymers is examined. The constituent polymers differ only in the number of alkyl units in the coupling chain between the mesogenic units and the polymer backbone. Mixtures composed of such materials exhibit both a lower critical solution temperature in the isotropic phase range and a upper critical solution temperature in the nematic phase range. The miscibility gap for 50/50 mixtures is of the order of approximately 30-degrees-C but there is minimal miscibility in the nematic phase range. This behaviour is observed for both mixtures involving nematic phases with the same sign of orientational coupling between the mesogenic units and the polymer chains and mixtures involving polymers with opposite signs of coupling. There is an asymmetry in the miscibility curve for a mixture containing polymers of opposite signs of coupling.