  The properties of semidilute polymer solutions are investigated at
equilibrium and under shear flow by mesoscale simulations, which combine
molecular dynamics simulations and the multiparticle collision dynamics
approach. In semidilute solution, intermolecular hydrodynamic and excluded
volume interactions become increasingly important due to the presence of
polymer overlap. At equilibrium, the dependence of the radius of gyration, the
structure factor, and the zero-shear viscosity on the polymer concentration is
determined and found to be in good agreement with scaling predictions. In shear
flow, the polymer alignment and deformation are calculated as a function of
concentration. Shear thinning, which is related to flow alignment and finite
polymer extensibility, is characterized by the shear viscosity and the normal
stress coefficients.
