Nanofluidic diode generated by pH gradient inside track-etched conical nanopore

A nanofluidic diode is produced with a track-etched single conical nanopore embedded in a polyethylene terephthalate (PET) film. It has a very strong current rectification behavior which depends on the surface charge densities and the solution salt concentration. We tried to control the current rectification properties by using asymmetric pH solutions on the two side of nanopore membrane, because that this arrangement could adjust the surface charge density distribution inside the nanopore since it depends on the local pH value. This nanofluidic diode is analogous to a bipolar semiconductor diode which is sensitive to the solution pH values.