Abstract: A multiblock copolymer includes a polysulfone repeating unit, a sulfonated polysulfone repeating unit and an ethylenic unsaturated group at a terminal of the multiblock copolymer. Also provided are a method of preparing the multiblock copolymer, a polymer electrolyte membrane prepared from the multiblock copolymer, a method of preparing the polymer electrolyte membrane, and a fuel cell including the polymer electrolyte membrane. The polymer electrolyte membrane that has a high ionic conductivity and good mechanical properties and minimizes crossover of methanol can be manufactured at low cost. In addition, the structure of the multiblock copolymer can be varied to increase selectivity to a solvent used in a polymer electrolyte membrane.

Abstract: A multiblock copolymer includes a polysulfone repeating unit of formula (1) below; a sulfonated polysulfone repeating unit of formula (2) below; and an ethylenic unsaturated group at a terminal of the multiblock copolymer: where l and m are integers of 1-200; each of R1 through R4 is independently hydrogen, fluorine, or a C1-C10 alkyl group that is unsubstituted or substituted by at least one fluorine atom; and X represents a tetraalkylamine cation. Provided are a method of preparing the multiblock copolymer, a polymer electrolyte membrane prepared from the multiblock copolymer, a method of preparing the polymer electrolyte membrane, and a fuel cell including the polymer electrolyte membrane. The polymer electrolyte membrane that has a high ionic conductivity and good mechanical properties and minimizes crossover of methanol can be manufactured at a low cost. In addition, the structure of the multiblock copolymer can be varied to increase selectivity to a solvent used in a polymer electrolyte membrane.