Spinodal decomposition kinetics of a mixture of liquid crystals and polymers

The spinodal decomposition (SD) kinetics of the mixture of polystyrene (PS) and a low molar mass liquid crystal (LC) (E7) has been studied by means of time-resolved small angle light scattering (SALS) and polarized optical microscopy (POM). It is found that, in the isotropic spinodal region, the mixture first undergoes an isotropic concentration fluctuation, and then the ordering process that occurs in pure LC will appear in the LC-rich phase after phase separation. In contrast to that, however, the concentration and orientation fluctuations take place simultaneously in an anisotropic spinodal region. A rapid phase separation via SD was observed in the anisotropic spinodal region due to the fact that the ordered LC phase excludes the polymer coils more strongly than the isotropic region.