Chiral Probes of Polymer Conformation

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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.