Equilibrium Aggregation in Perfluorinated Ionomer Solutions

There have been conflicting reports on the aggregation in Nafion, perfluorosulfonated ionomer, solutions. Scattering techniques show the existence of aggregates in ethanol and N-methylformamide, whereas studies using NMR- and ESR-spectroscopy suggest that Nafion dissolves molecularly in these solvents. The results from dynamic light-scattering presented in this paper indicates that an equilibrium between a small quantity of aggregates and loose polymers can explain all these data.

Fig. 1. Black bars: Distribution function from an inverse Laplace transformation of the field time correlation function in Figure 1. Gray bars: This distribution function converted to a number distribution. Sample taken directly from the autoclave (Nafion concentration 10 mg/mL). Detection angle = 40��.