Conductometric Analysis for the Formation of Poly(Vinylidene Fluoride)-Based Ion Track Membranes

Abstract

Poly(vinylidene fluoride) (PVDF) films were irradiated with 450 MeV 129Xe and 2.2 GeV 197Au ion beams and then the resulting latent tracks were etched in a 9 mol dm-1 aqueous KOH solution at 80ºC poured into an conductometry cell. At the same time, the evolution of cylindrical nanopores was monitored by measuring the conductance through the membrane. This in-situ measurement enabled us to examine how etching kinetics were affected by various experimental conditions, e.g., the parameters (mass and velocity) of the bombarded ions and cell potentials applied between the electrodes. The track etch rate, VT, radial rate, VR, and pore radius reaching the final plateau strongly depended on the deposited energy within each track, which is represented by the linear energy transfer (LET). Interestingly, applying a higher voltage to the cell promoted track etching up to breakthrough probably because electrophoretic migration of dissolved products occurred out of each pore.