The morphology of a cast thin film of a thermotropic main chain polyester was studied using optical microscopy and small angle light scattering (SALS). It was found that the SALS pattern arising from the nematic texture is a four-leaf clover pattern where the lobes are oriented at 0 ° and 90 °. The characteristic dimension associated with this pattern follows the coarsening of the texture upon annealing, thus providing a means of monitoring morphology changes in the film. Using this means it was possible to investigate the kinetics of texture evolution from the isotropic state to the final equilibrium nematic texture. It was found to be very fast. It was also found that the characteristic dimension associated with the pattern depends strongly on film thickness.
Посилання на статтю:
A light scattering study on films of a nematic main chain thermotropic liquid crystalline polymer / R. Silvestri* and L. L. Chapoyt // Polymer. – 1992. – Vol 33. – P. 2891-2896.