Effects of Chain Stiffness on Conformational and Dynamical Properties of Individual Ring Polymers in Shear Flow

Individual semiflexible ring polymers in a steady shear flow are studied by the multiparticle collision dynamics method combined with molecular dynamics simulations. We report the effects of chain stiffness on the conformational, dynamical, and rheological properties of ring polymers. When the Weissenberg numbers are smaller than unity, the behavior of semiflexible ring polymers is consistent with that of flexible ones. For larger Weissenberg numbers, the effects of chain stiffness are observed. We find that the radius of gyration tensor elements, the orientation resistance parameter, and the alignment distribution functions show strong stiffness dependences. The scaling behavior of tumbling motion corresponding to large conformational changes is found independent of chain stiffness, while the scaling behavior of tank-treading motion corresponding to the motion of monomers moving along the contour of the chain exhibits a chain stiffness dependence in the crossover regime from a flexible to a rigid ring polymer. Chain rigidities are found to have negligible effects on the polymer shear viscosity. The simulations reveal the similarities and differences in the nonequilibrium behavior of flexible and semiflexible ring polymers.