Electrical current pulsations through ion irradiated polymer foils in electrolytes

Funnel-type ion tracks were produced in thin polymer foils by swift heavy ion irradiation and subsequent treatment with both low concentration etchants and acids from two different sides. The funnel shapes consist of shallow etched cones and residual latent tracks and thus combine both their characteristic properties, rectification and current spike emission, in one track each. Arrays of spike-emitting tracks are known to exhibit phase-locked synchronous electrical pulsations in accordance with the neural network theory. These pulsations were studied here on arrays of funnel-type tracks for the first time. As expected, the results strongly depend on the track density. In foils with low track densities, synchronous oscillations are rare and rather unstable events, whereas foils with high track densities exhibit stable, strong and long-lasting pulsations. Insertion of 0.1 M KCl solution into tracks at low density improved the shape and regularity of the spuriously occurring spikes somewhat, as compared with water in these tracks.