Disclosed is a proton exchange membrane for use in fuel cells, which not only has improved proton conductivity and resistance to swelling caused by hot water but also has greater durability when used in a fuel cell, as well as a sulfonic acid group-containing segmented block copolymer constituting the proton exchange membrane, a membrane electrode assembly using the proton exchange membrane, and a fuel cell using the membrane electrode assembly. A sulfonic acid group-containing segmented block copolymer, which is a di- or multi-block copolymer including, within a molecule, at least one kind of hydrophilic segment and at least one kind of hydrophobic segment, a 0.5 g/dL solution thereof dissolved in N-methyl-2-pyrrolidone as a solvent showing a logarithmic viscosity measured at 30°C in the range of 0.5 to 5.0 dL/g, wherein the copolymer has at least one kind of hydrophobic segment represented by Chemical Formula 1, the segment has a structure bound to a group represented by Chemical Formula 2, and the hydrophilic segment has at least one kind of structure represented by Chemical Formula 3 or Chemical Formula 3-2.
本发明公开了一种用于燃料电池的质子交换膜,该质子交换膜不仅具有更好的质子传导性和抗热
水膨胀性,而且在用于燃料电池时具有更高的耐久性;还公开了一种构成该质子交换膜的含
磺酸基的嵌段共聚物、一种使用该质子交换膜的膜电极组件和一种使用该膜电极组件的燃料电池。一种含
磺酸基的嵌段共聚物,它是一种二嵌段或多嵌段共聚物,在一个分子内包括至少一种亲
水嵌段和至少一种疏
水嵌段,将其溶解在作为溶剂的N-甲基-
2-吡咯烷酮中的0.5克/分升溶液在30°C下测得的对数粘度在0.5至5.0dL/g,其中共聚物具有至少一种由
化学式1表示的疏
水段,该段具有与由
化学式2表示的基团结合的结构,亲
水段具有至少一种由
化学式3或
化学式3-2表示的结构。