Our previous report suggested that diffusion coefficients are higher in Nafion™‐impregnated Gore‐Tex (NIGT) membranes than in bulk Nafion membranes. This paper focuses on the mechanism of transport in NIGT membranes. We investigate the dependencies of the diffusion coefficients on the concentration of the electroactive species and on the weight fraction of Nafion in NIGT membranes. The apparent diffusion coefficients for and are directly proportional to the inverse weight fraction of Nafion in the NIGT membrane. We propose that the diffusion of the ions are coupled between the ions residing in the solution phase and the ions electrostatically bound to sites in the Nafion phase. By controlling the weight fraction of the Nafion in the NIGT membranes, we are able to vary and diffusion coefficients from to .
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Liu et al. (1990) studied this question.