To provide: a block copolymer that exhibits excellent proton conductivity even under low-humidification conditions, exhibits excellent mechanical strength and chemical stability, and when used in a polymer electrolyte fuel cell, allows high output and excellent physical durability; a polymer electrolyte material; and a polymer electrolyte form article and a polymer electrolyte fuel cell, using the same.
The block copolymer of the present invention includes each one or more of: a segment (A1) containing an ionic group; a segment (A2) not containing an ionic group; and a linker moiety connecting the segments. The segment (A1) containing an ionic group comprises a constituent unit represented by a specific structure. The polymer electrolyte material, the polymer electrolyte form article, and the polymer electrolyte fuel cell according to the present invention are manufactured by using the above block copolymer.