The goals of my research are a) to develop the methodology of solid state NMR for the characterization of solid polymers and b) to relate NMR measurements to important polymer properties. The work emphasizes elucidating morphological and/or chemical aspects of polymers. In semicrystalline polymers, interests include: the orientation of the non-crystalline chains in drawn materials, the partitioning of chemical and stereochemical defect structures between the crystalline and non-crystalline regions, the development of and morphology of aging-induced structures, and the impact of the crystallization of one blend component on the local distribution of a non-crystallizable blend component. Another area of interest is the characterization of glassy blends, both in the estimation of domain size as well as phase stoichiometry. We are currently studying mixing of components in photoresist formulations used in the fabrication of microelectronics. Nanofilled polymers are also being studied. We are interested in how the distribution of filler particles, as well as the changes in polymer dynamics and structure, combine to influence macroscopic properties. From a technique point of view, we make extensive use of the phenomenon of proton spin diffusion. We also, as much as possible, seek to use and develop techniques that are more broadly applicable to polymers in that they do not necessitate isotopic enrichment.
Honors and Awards
2004-Present: Scientist Emeritus, Polymers Division, NIST
Ph.D., Physical Chemistry, University of Illinois, 1968
B.A., Chemistry, Calvin College, 1963