Theoretical Investigation on Dynamics of Photopolymerization-Induced Phase Separation and Morphology Development in Nematic Liquid Crystal/Polymer Mixtures

A theoretical investigation of the dynamics of photopolymerization-induced phase separation (PIPS) and morphology development in a nematic liquid crystal (LC) polymer network mixture has been undertaken by incorporating photopolymerization kinetics into the coupled time-dependent Ginzburg-Landau (TDGL-Model C) equations. The simulation on the spatio-temporal evolution of the coupled LC concentration and orientation order parameters reveals that both morphological and scattering patterns for the orientation order parameter initially lag behind those of the concentration order parameter. However, the two fields evolve to the same spatial topologies with the progression of time. The PIPS dynamics is characterized only by the late stage of phase separation. We also observed a subtle change in the curvature of the growth curve associated with the onset of nematic ordering. The growth behavior and the simulated morphology consisting of LC droplets dispersed in a matrix of polymer appears the same for all compositions, except that the size gets somewhat larger with increasing LC concentration. Decreasing the rate of reaction increases the size of droplets due to the dominance of structural growth driven by thermal relaxation. Of particular interest is that our simulation captures the observed domain topologies. (C) 2000 American Institute of Physics. [S0021-9606(00)51839-X]

Electrically Tunable Microlens Array Formed by Pattern Polymerization of Photopolymerizable Mixtures Containing Liquid Crystals

An electrically tunable microlens array. The array is formed by pattern photopolymerization of photoreactive mixtures comprising a polymerizable material and liquid crystals; wherein the photopolymerization is characterized by the interaction of multiple-wave mixing. The liquid crystals are contained as droplets in regions between the polymerized material

20. Template Crystallization of Ultrahigh Molecular Weight Polypropylene Induced by Chain Orientation of Cocrystallized Ultrahigh Molecular Weight Polyethylene

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