Electron microprobe investigation into the diffusion of ions through polymers

Abstract

The objective of this investigation is to study the mechanism of ion diffusion through polymeric films and coatings. A better understanding of this phenomenon should aid progress with problems such as corrosion protection and desalination membranes. The authors wish to report some preliminary results obtained by means of electron microprobe analysis.

Salt diffusion through polymeric materials have been studied by several methods, e.g. chemical analysis [1], radioactive tracer techniques [2], and neutron activation analysis [3]. Although such methods yield useful information about average diffusion parameters, they provide no insight into details of diffusion on a localised and microscopic scale. The electron microprobe, on the other hand, can be used to determine the presence of specific ions in a volume element as small as 1μm in diameter. Therefore, microprobe analysis should be useful in determining local concentrations of diffusing ions and in examining the details of the diffusion process in polymers.