POLYMER ELECTROLYTE MEMBRANE HAVING IMPROVED DIMENSIONAL STABILITY

摘要

The invention provides dimensionally stable polymer electrolyte membranes (PEMs) that can be used to fabricate catalyst coated membranes (CCMs) and membrane electrode assemblies (MEAs) that are useful in fuel cells. A disclosed method of making a dimensionally stable (PEM) having in-plane dimensional stability comprises (a) providing a PEM having X^M and Y^M dimensions that define the X^M, Y^M plane of the PEM and a Z^M dimension perpendicular to said X^M, Y^M plane that defines the thickness of said PEM; and (b) treating said PEM to create strain in said X^M, Y^M plane to form a treated PEM, wherein said treated PEM does not significantly swell in at least one direction in the X^M, Y^M plane as compared to the Z^M dimension when contacted with water and methanol.