Renormalization-group calculation of excluded-volume effects on the viscometric functions for dilute polymer solutions

By combining nonequilibrium polymer kinetic theory with the renormalization-group method, one can obtain universal predictions for the material functions that describe the properties of dilute polymer solutions undergoing flow. For steady shear flow, double-sum expressions for the shear-rate-dependent excluded-volume contributions to the viscosity and the first normal-stress coefficient are obtained by employing a perturbation scheme previously developed for treating hydrodynamic-interaction effects. In the limit of long chains, these double sums are carried out to yield more explicit results for the zero-shear-rate viscometric functions. The effects of excluded-volume interactions on the shear-rate dependence of the viscometric functions and on experimentally observable, universal ratios involving zero-shear-rate normal-stress coefficients are discussed.