| abstract |
【Task】 Provided is a novel polymer electrolyte having high oxidation resistance, desulfonation hardly occurring even at high temperatures, and high proton conductivity as an electrolyte membrane and binder of a polymer electrolyte fuel cell. [Solution] A polymer electrolyte comprising a polymer sulfonic acid having a side chain having a structure in which an aromatic ring having a sulfonic acid group is linked by an electron-withdrawing linking group. The side chain may be a branched side chain or an unbranched side chain, but a branched side chain is preferred. Electron-withdrawing linking group, -CO -, - CONH -, - (CF 2) p- (p is an integer of from 1 to 10), - C (CF 3) 2 -, - COO -, - SO -, - It is selected from SO 2 −. And it has a side chain into which at least two sulfonic acid groups are introduced. |