On the structure of etched ion tracks in polymers

A simple model describing the radial structure of latent tracks produced by energetic ions in polymers is presented and used for examination of the process of preferential track etching and determination of the shape of the etched pores. The model is based on the assumption that the local composition of the latent track results from chemical reactions of transient degradation products created by ion passage, but it does not take into account details of the whole process. In accordance with the established idea the model calculations lead to the latent track structure with an easily etchable core surrounded by a relatively thin layer of cross-linked structures and a far reaching halo with a progressively decreasing concentration of the degradation products. The etching of the latent track with such a structure leads to funnel-type pores which have been observed in recent conductometric experiments.