Easier sieving through narrower pores: fluctuations and barrier crossing in flow-driven polymer translocation

We show that the injection of polymer chains into nanochannels becomes easier as the channel becomes narrower. This counter intuitive result arises because of a decrease in the diffusive time scale of the chains with increasing confinement. The results are obtained by extending the de Gennes blob model of confined polymers, and confirmed by hybrid molecular dynamicslattice-Boltzmann simulations. Polymer chains in solution can translocate through nanochannels at sufficiently high flow rate. We show that due to Brownian motion of the chain within the constriction, the translocation flow rate increases for wider nanopores.