Two-dimensional active polar semiflexible polymer under shear flow

Abstract: The nonequilibrium structural and dynamical properties of semiflexible active polar polymers subject to linear flow are studied by numerical simulations. Filaments are confined in two dimensions and immersed in a fluid described by the Brownian Multiparticle Collision Dynamics approach. The applied shear flow causes conformational changes of a polymer, aligns it along the flow direction, and induces a tumbling motion at large flow rates. In an intermediate, activity-dependent shear-rate regime, a characteristic scaling exponent for the mean-square end-to-end distance along the gradient direction is observed. This exponent appears to be determined by the semiflexibility of the polymer. The tumbling dynamics exhibits a characteristic time, with a stronger dependence on the Weissenberg number than that of flexible active or passive polymers. Activity strongly impacts the rheological properties of the semiflexible polymers, and even implies a negative viscosity for weak flows. At very large values of the shear rate, shear dominates over activity and passive-polymer behavior is assumed.