INFLUENCE OF SURFACE CHARGE AND ION CONCENTRATION ON CURRENT RECTIFICATION IN CONICAL NANOPORES

摘要

For ion transport in conical nanopores, we report the impact on ion current from the relative contributions of (1) the potential dependent effect of concentration polarization, (2) the permselective transport of counterions to the surface charge, and (3) the conductivity of the bulk solution. Through both experimental and numerical studies, we observe how ion transport behavior is defined by these contributions at different surface charge densities and ion concentrations. Notably, for a given geometry, the magnitude of the surface charge density shifts the concentration at which peak current rectification occurs.