The objective of this work is to study diffusion and transport in polymer solutions. The primary physical method will be light scattering spectroscopy, which is a non-invasive probe of Brownian motion and diffusion in equilibrium complex fluids. Measurements of the diffusion of polymer chains through solutions containing a second type of polymer chain will be made and compared with extant models of polymer dynamics. Observations will be made on the diffusion of mesoscopic (200A-micrometer) probe particles through polymer solutions. Of particular interest are the behavior of probe particles in polymer solutions at very large concentrations and molecular weight, the temperature dependence of the probe diffusion coefficient, and the behavior of probe particles in polymer solutions in which the polymer has an unusually wide molecular weight distribution. A effort will be made to involve undergraduate students in real, publishable research, thereby potentially enhancing the country's scientific and engineering manpower pool. Theoretical models relevant to these experiments will be improved.
