Ion transport through track etched polypropylene membrane

The transport properties through track etched polypropylene (PP) of 25 μm have been examined. The asymmetric pores in PP have been prepared by track etching technique. The PP membrane was exposed by α-source (95Am241). Irradiated PP membrane placed into an electrolyte cell and etched from one side while stopping medium protected other side. The etching is controlled by monitoring the electric current and to be stopped shortly after the breakthrough, which, is observed as a sudden increase in current, indicating that the two chambers of cell are connected through the pores. Asymmetric etching condition allows the preparation of charged pores of conical shape. The resulting conical pores rectify ion current. The voltage current characteristics is strongly non-linear, comparable to that of an electrical diode.