Proton exchange membrane

From Freepedia

A proton exchange membrane is a type of semipermeable membrane, generally made from ionomers. Proton exchange membranes (PEMs) are designed to conduct protons, or rather hydrogen ions, across the membrane, while being impermeable to gasses such as oxygen or hydrogen. This is their essential function when incorporated into a proton exchange membrane fuel cell: separation of reactants and transport of protons. PEMs can be made from either pure polymer membranes or from composite membranes where other materials are imbedded in a polymer matrix. One of the most common and commercially available PEM materials is Nafion which is made by DuPont. While Nafion is an ionomer with a perfluorinated backbone like Teflon, there are many other structural motifs used to make ionomers for proton exchange membranes. Many use polyaromatic polymers while others use partially fluorinated polymers.