Phase behaviour and morphology of polymer/liquid crystal blends

Abstract

The phase behaviour of blends of poly(ethylene oxide) (PEO) with the liquid crystal p-azoxyanisole (PAA) has been studied by differential scanning calorimetry and optical microscopy. This system exhibits partial miscibility of the components in the molten state (at temperatures above 337 K). The melting temperature and enthalpy of the PAA phase has been found to depend on the blend composition, whereas the melting behaviour of the polymer phase remains quite unaltered. The occurrence of the PAA nematic phase, dispersed within an isotropic liquid phase, has been observed at high concentrations of liquid crystal. The morphology of the blends in the solid state changes largely with the PAA content, depending on the solubility of the components in the liquid phase.