Ion track symmetric and asymmetric nanopores in polyethylene terephthalate foils for versatile applications

In this report we present several fabrication methods which allow production of ion track nanopore membranes with different pore configurations. Polymer foils, typically polyethylene terephthalate with a thickness of 5–23 μm, are irradiated with accelerated heavy ions (energy of 1–10 MeV/u) and then subjected to different physico-chemical treatments. Depending on the procedure, symmetric or asymmetric pores with nanoscale-sized narrowing are obtained. The asymmetric configurations include conical, funnel-like and bullet-like shapes. In electrolyte solutions the asymmetric nanopores exhibit diode-like properties which strongly depend on the pore shape. The peculiar features of such pores provide a basis for various applications.