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

研究综述：流体微结构的一种重要形式是所谓的液晶。在本项目中，将在超临界流体条件下合成高纯度的聚合物液晶，用于研究热致行为和在激光系统中的新应用。对结构-性质关系的良好理解将使聚合物液晶的分子设计能够在涉及界面和传输过程的一些技术领域中得到预期的应用。独特性/创新：如果成功，建议的方法是创新的，因为可以以高成本高效地制备高纯度的聚合物液晶，以满足高能激光技术的需求。为了达到激光技术所要求的光学均匀性，提出了聚合和提纯同时进行的方法。文献中报道的聚合物液晶一直是在液体溶剂中制备的，在这种情况下，后续去除剩余溶剂和未反应单体以及细化分子量分布都是困难的。意义/技术影响：一种经济的高纯度聚合物液晶制备方法应该会对许多技术领域产生深远影响。高选择性生物活性膜的合成、高可溶性药物的受控给药、热敏气体和蒸气屏障、光活性聚合物等都是从这项研究的结果中获得潜在好处的应用实例。与激光技术相关的对聚合物液晶的重视应该对非线性光学效应的诱导有直接的贡献，包括频率转换、四波混频、激光光束自聚焦和电光开关。该项目的最终目标是基于对高纯度液晶样品的广泛分析，提供结构-性质关系，从而为现有和新应用的分子设计提供良好的基础。

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.