Self-consistency of hydrodynamic models for the zero-shear viscosity and the self-diffusion coefficient

The hydrodynamic model treatments of the zero-shear viscosity eta and the self-diffusion coefficient D-s of polymers in nondilute solution are shown to be self-consistent. Hydrodynamic models for polymer dynamics in nondilute solution postulate that interchain hydrodynamic interactions dominate other interchain forces. These models predict concentration dependences of eta, D-s, and other transport coefficients. Previously published predictions of eta and D-s include a single hitherto-undetermined physical parameter, whose value is here obtained from the concentration dependence of eta. When this parameter is supplied to the self-diffusion calculation, the concentration dependence of D-s is entirely determined with no adjustable parameters. Comparison is made with the literature. The model prediction for D-s is in excellent agreement with data on solutions of linear and three-armed star polymers covering a fall range of polymer concentrations and homologous polymers spanning nearly 4 orders of magnitude in polymer molecular weight.