Specific Interactions in Polymer Systems

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This research involves studies of specific interactions in polymer systems. One part of the work seeks to obtain a fundamental understanding of the interplay between microstructure, interactions, conformation and phase behavior in polymer blends. A comprehensive study the effect of stereoregularity on the ability of functional groups to hydrogen bond will be performed. The effect of spacing these groups along the chain on the accessibility of these groups will also be investigated through the synthesis and characterization of appropriate copolymers. This work will be complemented by the second part of the proposed research, which involves studies of the shapes and widths of bands in these strongly interacting systems and how these are affected by phase changes and relaxation processes. It is widely recognized that a wealth of information on molecular dynamics lies buried in the shapes of infrared bands and Raman lines. The extent to which useful information on picosecond dynamics can be obtained from the spectra of polymers will be evaluated by means of a systematic experimental study. %%%The phase behavior of polymer blends is of considerable practical importance. Finding polymers that mix at the molecular level (most do not) can lead to materials with novel properties. Even polymers that phase-separate can have important properties, such as enhanced impact resistance, providing that the size of the phase separated domains are controlled. Accordingly, understanding the role of interactions in making miscible or compatible blends, the focus of this research, is important in the development of new materials. This research will also contribute to education through the mechanism of involving both undergraduate and graduate students in laboratory work, thus teaching them the fundamentals of spectroscopic and other techniques. More uniquely, work supported on previous NSF awards that resulted in CD based monographs, complete with animations and interactive programs, will be extended to cover hydrogen bonding and the thermodynamics of polymer mixtures.***