State of understanding of Nafion

A comprehensive review of the state of understanding of the fundamental structure and properties of Nafion perfluorosulfonate materials is presented based on recent as well as historical literature that either survived the test of time or influenced further research trends. Through the collective information acquired from the detailed works of many research groups and institutions, a broader understanding of this technologically important material has emerged. It is emphasized that although many of these contributions have exposed a significant number of critical relationships between structure and the unique properties of Nafion, much more remains to be learned.