Kinetics of the ordered phase growth at the phase transition from the isotropic to cholesteric state in a main chain liquid crystalline polymer

The optical microscope investigation of the isotropic- ordered phase transition in a main chain LC polymer and subsequent statistical treatment of the microscopic images allowed recognition of three regimes of the ordering: non-stationary regime which is characterized by increasing rate of the droplets growth; stationary regime; within it the ordered phase grows with a constant rate, and the coalescence regime for which the rate of the droplets growth deceases. Linear interpolation of the time dependence of the mean droplets diameter in log–log scales allowed conclude that within the stationary regime of the cholesteric phase growth, log <d> is a linear function of log t, whereas within the coalescence regime, <d> is proportional to t ^1/2 as expected from the theory of phase separation binary liquids. The time of beginning and duration of both growth regimes of the phase transition for the main chain LC polymer exceed those for low molecular weight LC compounds. This is caused by lower mobility of macromolecules in comparison with that for low molecular weight LC compounds.