Polymer Dynamics on Surfaces and in Complex Media

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9711226 Yu The proposed research is directed at the chain dynamics on surfaces of water, polymer covered glasses and silicon wafers in order to investigate the influence of confined geometries on the chain motions. In addition, interest is focused on the chain diffusion in highly interacting systems wherein the diffusants are known to impact on rheology of the entire system even when they are present as minor components. With the interfacial dynamic techniques of surface fluorescence recovery after photobleaching, surface quasielectric light scattering, in-plane steady shear viscosity by canal flow, in conjunction with the interfacial static techniques of atomic force microscopy, x-ray photon spectroscopy, neutron reflectivity and spectroscopic elllipsometry, the PI will examine 1) polyelectrolyte diffusion on functionalized glass surfaces, 2) polymer monolayer shear viscosity and dilational viscoelasticity at the air/water interface, 3) polymer diffusion as a function of film thickness, and 4) polyelectrolyte diffusion on planar surfaces consisting of polar heads of surfactant molecules. %%% The purposes of the proposed research are to come up with better materials design methods covering a wide range of advanced organic materials that are used in many different applications such as in artificial organs and implants, all spill confinement materials, drug delivery devices, and lubricants. This study is at the molecular level. ***