The Cluster—Network Model of Ion Clustering in Perfluorosulfonated Membranes

A model for ionic clustering in "Nafion" (registered trademark of E. I. du Pont de Nemours and Co.) perfluorinated membranes is proposed. This "cluster-network" model suggests that the solvent and ion exchange sites phase separate from the fluorocarbon matrix into inverted micellar structures which are connected by short narrow channels. This model is used to describe ion transport and hydroxyl rejection in "Nafion" membrane products. We also demonstrate that transport processes occurring in "Nafion" are well described by percolation theory. The solvent and ion exchange sites in "Nafion" perfluorinated membranes phase separate from the fluorocarbon matrix to form clusters (1-5). This ionic clustering will not only affect the mechanical properties of the polymer (1), but should also have a direct effect on the transport properties across these membranes (2). In addition the exchange sites in the resin are strongly acidic and the polymer is extremely hydrophilic. Combined with the polymer's