Patent ID: 8519081

Claim:
A polymer comprising a repeat unit represented by the following Chemical Formula 1: Wherein, X is Ar 1 , and Ar 1 is substituted or unsubstituted C6-20 arylene group; M 1 and M 2 are independently hydrogen or inorganic cation; a+b=5, c+d=5, a and c are independently an integer of from 1 to 5; e and f are independently an integer of from 0 to 4; R 1 , R 2 , R 3 and R 4 are independently hydrogen, C1-20 linear or branched alkyl, C2-20 alkenyl, C2-20 alkynyl, C5-20 cycloalkyl, C6-20 aryl, C2-20 heteroaryl, C7-20 alkylaryl, or C1-20 alkoxy group; and, n, which is a polymerization degree, is 10 to 10,000, wherein the polymer is obtained by using chlorosulfonic acid in a sulfonation reaction, and wherein the polymer is included in a polymer electrolyte membrane of a fuel cell.