Expedited Award: Thermotropic Behavior and Novel Applications for Polymer Liquid Crystals

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Research Summary: One important form of fluid microstructures is the so-called liquid crystal. In this project, highly pure polymer liquid crystals will be synthesized under supercritical fluid conditions for the investigation of thermotropic behavior and for novel applications in laser systems. A sound understanding of structure-property relations will permit molecular design of polymer liquid crystals for desired applications in a number of technological areas involving interfacial and transport processes. Uniqueness/Innovation: The proposed methodology, if successful, is innovative in that polymer liquid crystals can be prepared cost effectively in high purity to meet the needs of high energy laser technology. To achieve the optical homogeneity as demanded in laser technology, it is proposed to carry out polymerization and purification simultaneously. Polymer liquid crystals reported in the literature have been consistently prepared in liquid solvents, where the subsequent removal of remaining solvent and unreacted monomer and the refinement of molecular weight distribution are both difficult to accomplish. Significance/Technical Impact: An economical approach to the preparation of polymer liquid crystals in high purity should have profound impact on a number of technological areas. The synthesis of highly selective biologically active membranes, controlled administration of highly soluble drugs, thermally sensitive gas and vapor barriers, photoactive polymers, are examples of applications with potential benefits from the results of this proposed study. The emphasis on polymer liquid crystals in relation to the laser technology should have immediate contributions to the induction of non-linear optical effects including frequency conversion, four wave mixing, laser beam self-focusing, and electro-optical switching. The ultimate goal of this project is to furnish structure-property relations based on extensive analyses of highly pure liquid crystal samples, thereby providing a sound basis for molecular design for existing and new applications.