Phase separation dynamics of a polymer dispersed liquid crystal

Phase separation in a polymer dispersed liquid crystal (PDLC), consisting of a main chain liquid crystal (E7) and polymethyl methacryhte (PMMA), was studied by means of light scattering and optical microscopy. The PMMAm mixture exhibits an upper critical solution temperature (UCST), overlapping with a nematic-isotropic transition of the E7 liquid crystal. Several temperature quenches were undertaken by rapidly transferring the 60140 PMMAIE7 from a single phase (95 OC) to an unstable region (25.35 and 45 OC) and by subsequently monitoring the time-evolution of scattering profiles. The time-evolution of structure factor reveals a cross-over of a kinetic exponent from -0.33 to -0.6 or larger slopes at a shallower temperature quench. Multiple droplets appear under a polarized microscopic investigation. Concurrently, nematic disclinations develop within the droplets and annihilation occurs as droplets coalesce.