Chiral Probes of Polymer Conformation

在化学系有机动力学项目的资助下，来自理工大学的Mark M.Green教授和共同研究人员S.Matsuoka、H.Morawetz和B.Garetz将研究聚合物构象的手性探针。含有手性单体基团的手性聚合物表现出相同的光学活性性质，无论是由对映体纯的单体形成的，还是由对映体过量很小的对映体混合物形成的。结果被理解为协同效应，其中聚合物的优选构象由局部构象效应驱动。这个项目将把这一概念扩展到液晶聚合物、树枝状大分子和聚合物无定形固体，到目前为止，这一概念只适用于溶液中的线性(多异氰酸酯)聚合物。它还将应用开发的概念来研究合成聚合物中二级和三级结构的基本问题，以及了解溶剂分类(工业上称为局部组成效应)。材料性能的系统性和可预测性变化为优化其行为提供了一种主要策略。这项工作将为研究和控制聚合物材料的性能探索一条新的途径。要研究的材料为放大小的光学效应提供了机会，并且例如为将该材料用作基于圆偏振光的光开关提供了机会。

With funding from the Organic Dynamics Program of the Chemistry Division, Professor Mark M. Green and co-investigators S. Matsuoka, H. Morawetz, and B. Garetz, all of Polytechnic University, will study chiral probes of polymer conformation. Chiral polymers containing chiral monomer groups exhibit optical activity properties which are identical whether formed from monomers which are enantiomerically pure or formed from a mixture of the enantiomers in which the enantiomeric excess is only slight. The result is understood as a cooperative effect in which the preferred conformations of the polymer are driven by local conformational effects. This project will extend the concept, so far proved only for linear (polyisocyanate) polymers in solution, to liquid crystalline polymers, dendrimers, and polymeric amorphous solids. It also will apply the concepts developed to study fundamental questions of secondary and tertiary structure in synthetic polymers, as well as to understand solvent sorting (called local composition effects industrially). Systematic and predictable variation of the properties of materials offers a prime strategy for optimization of their behavior. This work will explore a new approach to studying and controlling properties of polymeric materials. The materials to be studied provide an opportunity for amplification of small optical effects and, for example, for use of the materials as optical switches based on circularly polarized light.