ANALYTICAL ELECTRON-MICROSCOPY OF NAFION ION-EXCHANGE MEMBRANES

Ion exchange membranes, widely used in many electrochemical techniques, have become of major interest in water purification as part of new environmental technologies and in the highest purification of water for industrial purposes. Nafion 117, a product of the Du Pont Company showing high ionic conductivity and good mechanical properties, is a promising candidate for future applications. The principles of analytical electron microscopy were used to study the ion exchange membrane. Imaging showed ionic percolation in the polymer. No staining method was applied, to ensure artefact-free images of the membrane. Electron diffraction gives additional information about the cross-linked structure while EDS and EELS data provide information on chemical composition and ion exchange efficiency. Results were obtained using two independent methods of specimen preparation.