Radiation effects of swift heavy ions in polymers: Determination of nanoshapes from electro-conductivity

The shape of ion track nanopores in polymers depends on the radial distribution of radiation effects. While chain scission dominates in the track core (r < 5 nm), cross linking dominates in the track halo (5 < r < 50 nm). Therefore, compared with the pristine material, the track core etches at an increased speed, while the track halo etches at a reduced speed. The counteracting effects thus lead to a pore profile that differs from the idealised double-cone profile. We describe an algorithm for retrofitting the pore profile from electro-conductivity data. The technique is supported by field emission SEM in polyethylene terephthalate (PET) and polycarbonate (PC). The results are relevant to biomedical and sensing applications of “conical” and “doubly-conical” nanopores.