Ion conductive membrane made from a block copolymer and methods of making a block copolymer

A product comprising:

• a block copolymer for use as a solid polymer electrolyte, said block copolymer having at least first and second segments, the first segments being provided with acidic substituents for proton transport and the second segments having substantially no acidic substituents and serving for the mechanical integrity of the solid polymer electrolyte, and wherein said first segments have the general formula
• in which:
• Y represents —SO2—,
• end groups Z represent a halogen (F, Cl, Br, I),
• Q represents —SO3H, —SO3−M+, —COOH, —COO−M+, —PO3H2, —PO3H−M+, or —PO32−2M+ where M is a metal such as Na or K,
• with m being between 5 and 200,
• with the bridges Y between sequential aromatic rings being the same or different and being selected from any of the above atoms or groups listed for Y, and
• with Q not having to be present in every aromatic ring.