POLYMER ELECTROLYTE FOR SOLID POLYMER TYPE FUEL CELL AND FUEL CELL

A polyelectrolyte for a solid polymeric fuel cell comprising an aromatic polyether sulfone block copolymer comprising a hydrophilic segment containing sulfonic acid groups and a hydrophobic segment having no sulfonic acid group at a hydrophilic segment weight fraction W2 to hydrophobic segment weight fraction W1 ratio falling within a range of 0.6