BLOCK PERFLUOROSULFONIC ACID IONOMER FOR IMPROVED FUEL CELL PERFORMANCE

摘要

A block copolymer perfluorosulfonic acid ionomer is disclosed with low averageequivalent weightcomprising both hydrophilic and hydrophobic blocks of relatively low andrelatively high equivalentweights respectively. Such ionomer can be made by polymerizing a suitablemixture of hydrophilic andhydrophobic monomers and then, upon reaching a certain molecular weight,performing a secondpolymerizing using the same monomers but with a greater relative amount ofhydrophobic monomer. Suchionomer should provide both improved mechanical properties and performance insolid polymer electrolytefuel cells. It is expected that the presence of the larger hydrophobic blocksand the larger hydrophilic blockswould enhance mechanical stability and increase proton conductivityrespectively, particularly under hotand dry operating conditions in automotive fuel cell applications.