The Effect of Composition of Nafion Deposition Solutions on the Diffusional Properties of the Films

The properties of Nafion films on electrodes were studied as a function of the water content in the deposition solutions (0.1% Nafion in mixed ethanol/water). The rate of loading and unloading (i.e., ion-exchange) of the complex ion RuCbpy) 3 2+ , loading into films which were thermally treated, and penetration of the anion Fe(CN) 6 4+ were examined. All these measurements show a nearly linear dependence of the voltammetric peak currents (for the oxidation of the incorporated ions) on the percentage of water in the deposition solutions. These results lead to the conclusion that films that are cast from solutions of higher water content have more «open» structures that allow faster diffusion of ions