Proton exchange membrane
A proton exchange membrane , often Proton Exchange Membrane (PEM) or Polymer Electrolyte Membrane (PEM) called, is a generally made of ionomer prepared semipermeable membrane . PEMs are permeable to protons , while the transport of gases such as oxygen or hydrogen is prevented. For this purpose, the PEMs are primarily used in polymer electrolyte fuel cells . They are made either from pure polymer or from composite membranes in which other materials are embedded in a polymer matrix. The most widely used PEM commercially is Nafion from the DuPont chemicals group .
