Gaussian approximation and Brownian dynamics simulations for Rouse chains with hydrodynamic interaction undergoing simple shear flow

Abstract

A bead-spring-chain model including hydrodynamic-interaction effects is used to calculate the rheological properties of dilute polymer solutions undergoing steady shear flow. The hydrodynamic fluctuations are explicitly taken into account within the context of the recently developed Gaussian approximation for the hydrodynamic interaction. In this Gaussian approach expressions for the non-Newtonian stress tensor at arbitrary shear rate are calculated. For short chains, the shear-rate–dependent predictions for the viscometric functions are presented. Also, the Brownian dynamics simulation technique is applied to determine exact rheological behavior of the model. Comparing the simulation results to the corresponding predictions of the Gaussian, consistent-averaging, and preaveraging approximations the validity and the superiority of the Gaussian method is clearly demonstrated.