Reversible Pore Gating in Aqueous Mixtures via External Potential

We examine theoretically porous membranes in aqueous mixtures. We show that large membrane pores can be reversibly gated from `off' (co-solvent-rich, poor conductor of ions and other solutes) to 'on' (water-rich, good conductor) states by an external potential. The transition voltage or charge for switching depends on the membrane hydrophilicity/hydrophobicity, the salt content, the preferential solvation of the salt ions, and the temperature. These parameters also determine whether the filling transition is abrupt or gradual.