Pressure Modulation of Ion Conductance and Selectivity in Nano-channels with Weakly Overlapping Electrical Double Layers

Abstract

This work numerically investigates the I-V responses of nanofluidic channels under external pressure difference. Poisson-Nernst-Planck-Stokes simulations demonstrate that ion conductance in nano-channels is influenced by the interplay between convective flow and concentration polarization. The extending degree of the ion depletion zone inside the channel is found to be improved at a forward pressure, resulting in a lower ionic conductance and vice versa. Furthermore, the ionic selectivity is increased (or decreased) by a positive (or negative) pressure in comparison with the case driven by electro-osmosis only. All these findings suggest that nano-channel’s electrical property can be modulated by external pressures, thus implying potentials in practical nanofluidic applications.