Development of micro/macro-scale dynamic characterization system and its application to polymer gel science

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Polymer gels consist of two components of network polymer chains and solvent. Further, a third component such as a low molecular-weight compound or polymer is often contained in the gels. Polymer gels have attracted considerable attention from the point-of-view of various physical and chemical properties. For example, hydroelectrolyte gels show a dramatic change in volume in response to change in solvent composition, pH, ionic strength and temperature. They contract upon application of an electric field. Further, water-swollen polymer gels can convert chemical energy into mechanical energy. These properties lead to the vitality of polymer research and development of a diversity of interests in polymer gel systems. In order to develop new polymer materials, polymer gel design has been performed on the basis of advanced polymer science and technology. The properties of polymer gels are closely related to their structures and dynamics. From such situations, the establishment of methods for elucidating the structures and dynamics is important for making reliable polymer gel design and developing new advanced polymer gels and also is important for polymer science. From such a background, we have successfully developed by high field-gradient spin-echo(PFGSE) NMR system and NMR imaging system capable of determining very small diffusion coefficients of 10^-10 - 10^-11 cm^2/s and three-dimensional image pattern about spin density and diffusion coefficient distribution, and have elucidated structure and dynamics of polymer gels.