Effect of etching conditions on pore shape in etched ion-track polycarbonate membranes

We have undertaken a systematic investigation of the influence of methanol and applied transmembrane potential on the shape of conical pores produced by the track-etch technique. Heavy ion tracks in polycarbonate foils were chemically etched in an electrolytical cell under various conditions (different methanol content in the etchant, and applied potentials). It is found that the cone angle of the conical nanopore is dependent on the amount of methanol present in an alkaline etching solution as well as on the applied transmembrane potential. A combination of both these techniques is proposed to obtain conical nanopore with more exaggerated base opening. Controlling these conditions provide a route to fabricate controlled shape pores in polycarbonate membranes that have potential applications in a wide array of fields.