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

研究综述：流体微观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聚合物液晶，用于研究热致性行为和在激光系统中的新应用。对结构-性能关系的充分理解将使聚合物液晶的分子设计在涉及界面和传输过程的许多技术领域得到所需的应用。独特性/创新性：所提出的方法，如果成功，是创新的，因为聚合物液晶可以以高纯度的成本有效地制备，以满足高能激光技术的需求。为了达到激光技术要求的光学均匀性，提出了聚合和纯化同时进行的方法。文献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，后续的残余溶剂和未反应单体的去除以及分子量分布的细化都很难完成。意义/技术影响：一种制备高纯度聚合物液晶的经济方法将对许多技术领域产生深远的影响。高选择性生物活性膜的合成，高可溶性药物的控制给药，热敏气体和蒸汽屏障，光活性聚合物，是本研究结果潜在益处的应用示例。强调聚合物液晶与激光技术的关系，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、激光束自聚焦和电光开关。该项目的最终目标是在对高纯度液晶样品进行广泛分析的基础上，提供结构-性质关系，从而为现有和新的应用提供良好的分子设计基础。

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.