Abstract
The non-equilibrium structural and dynamical properties of flexible polymers confined in a square microchannel and exposed to a Poiseuille flow are investigated by mesoscale simulations. The chain length and the flow strength are systematically varied. Two transport regimes are identified, corresponding to weak and strong confinement. For strong confinement, the transport properties are independent of the polymer length. For weak confinement or sufficiently strong flow and far from the channel center, the local stretching is similar to that of a polymer in simple shear flow, but in the central part the polymer exhibits a different behavior. The analysis of the long-time tumbling dynamics of short polymers yields a non-periodic motion with a sublinear dependence on the flow strength.