Ion mobility and ionic conductance in nanodevices are known to deviate from bulk behavior, a phenomenon often attributed to surface effects. Using coarse-grained molecular dynamics simulations, we have demonstrated that dielectric mismatch between the electrolyte and the surface material can qualitatively alter ionic transport in a counterintuitive manner: Instead of following the polarization-induced modulation of the concentration profile, mobility is affected by the surface-polarization-induced changes in the ionic atmosphere near the interface and by an emerging polarization force, which is oriented parallel to the surface.

An analogous phenomenon exists in nanochannels functionalized with polyelectrolyte brushes. Therein, surface polarization can drastically affect the ion conduction via altering the polymer-ion binding near the interface, even turning the non-monotonous dependency of ion mobility from polymer density to monotonous.