Equilibrium Dynamics and Shear Rheology of Semiflexible Polymers in Solution

We study the structure and dynamics of semidilute solutions of semiflexible polymers at rest and under shear using hybrid molecular dynamics simulations that take hydrodynamic interactions into account. We show that the polymer center-of-mass diffusion coefficient significantly decreases with increasing chain stiffness at fixed monomer density. The zero-shear viscosity shows a corresponding increase due to the intermolecular interactions of stiffer chains. We apply steady shear flow to the polymer solutions and show that at high shear rates the flow properties become almost independent of polymer stiffness. We characterize the polymer conformations under shear and find that in this regime polymers are elongated and aligned along the flow direction, but semiflexible polymers surprisingly form an increased number of hairpin-like conformations due to increased tumbling.