Michael J. Winokur Professor Address/E-mail Program Affiliations Education Fields of Interest Publications Summary >>> Extended Homepage <<<

Contact Information

B209 Sterling Hall 475 North Charter Street Madison, WI 53706

Tel: 608/263-7475 E-mail: winokur@ewald.physics.wisc.edu

Program Affiliations

• Materials Science Program
• Physics

Education

• PhD, University of Michigan

Fields of Interests

• structure of linear and branched macromolecular hosts
• phase transitions
• conducting polymers

Publications

• G. Mao, M.J.Winokur and F.E.Karasz, Dual Alkali-metal-ion Channel Structures in Poly(paraphenylene vinylene), Phys. Rev. B 53, R463, (1996).
• T.J. Prosa, J. Moulton, A.J. Heeger and M.J. Winokur, X-ray Scattering Line-Shape Analysis of the Thermotropic Liquid Crystal Transition in Poly(3-dodecylthiophene), Macromolecules 32, 4000 (1999).
• G. Mao, M.J.Winokur and F.E.Karasz, The Generalized Anisotropic Planar Rotor Model and its Application to Polymer Intercalation Compounds, Phys. Rev. Lett., 83, 2588 (1999).
• W. Chunwachirasiri, R. West and M.J. Winokur, Polymorphism, Structure and Chromism in Poly(di-n-octylsilane) and Poly(di-n-decylsilane), Macromolecules, in press (2000).

Summary

The primary focus of our current research is the study of structure and structural evolution within conducting polymer hosts in their pristine state, during processing and after intercalation by secondary guest species. This structural information is an essential component for developing a comprehensive understanding of conducting polymer transport. Moreover, these systems exhibit unusual structural properties that arise from the competing interactions at molecular length scales. Much of our recent work has employed traditional Rietveld refinement methods (suitable for crystalline hosts) that have been optimized for polymeric materials. These core studies are now being supplemented by a number of newer structural analyses aimed at resolving key aspects of the local molecular ordering in semi-crystalline and amorphous systems.

A second research area recently initiated is the study of molecular ordering within linear alkane derivatives and other model molecular hosts under conditions of extreme shear. The major goal in this undertaking is to obtain quantitative measures of the local structural order as a function of key system parameters (i.e., increasing shear, temperature, concentration) and relate these experiment results to existing theoretical and computation model predictions.