State of Understanding Polymer Electrolyte Membranes

The first perfluorinated ionomer was developed in the early 1960s by Walther G. Grot at E.I. DuPont de Nemours (Grot, 2011). It became famous under the trade-name Nafion. From the mid-1960s, Nafion found use as an electrochemical separator material in the chlor-alkali industry. Exploration of Nafion as a fuel cell electrolyte started at about the same time. 

PFSA ionomers are linear statistical copolymers of hydrophobic polytetrafluo-roethylene backbones with randomly grafted vinyl ether sidechains, terminated by sulfonic acid (-SO3H) head groups. Materials of this type vary in the chemical structure of the pendant sidechains. Other materials modifications are done to reduce membrane thickness and increase the lEC, through increasing the grafting density 

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