Amine neutralized sulfonated block copolymers and method for making same

A process for preparing a membrane comprising a sulfonated block copolymer, said process comprising:

• providing a solution comprising an organic solvent and the non-neutralized block copolymer in micellar form, and
• adding at least one amine to the solution, wherein the amine is a multi-functional amine having from two to four nitrogen functionalities, and comprises at least two nitrogen functionalities which are linked to one another via a linear, branched, or cyclic aliphatic bridging moiety, and subsequently forming said solution into a membrane comprising the sulfonated block copolymer,
• wherein the sulfonated block copolymer prior to neutralization has at least one end block A and at least one interior block B wherein each A block contains essentially no sulfonic acid or sulfonate ester functional groups and each B block is a polymer block containing from about 10 to about 100 mol percent sulfonic acid or sulfonate ester functional groups based on the number of monomer units of the B block and which are not neutralized,
• wherein each A block comprises one or more segments selected from polymerized (i) para-substituted styrene monomers, (ii) ethylene, (iii) alpha olefins of 3 to 18 carbon atoms, (iv) 1,3-cyclodiene monomers, (v) monomers of conjugated dienes having a vinyl content less than 35 mol percent prior to hydrogenation, (vi) acrylic esters, (vii) methacrylic esters, and (viii) mixtures thereof;
• each B block comprises segments of one or more vinyl aromatic monomers selected from polymerized (i) unsubstituted styrene monomers, (ii) ortho-substituted styrene monomers, (iii) meta-substituted styrene monomers, (iv) alpha-methylstyrene, (v) 1,1-diphenylethylene, (vi) 1,2-diphenylethylene and (vii) mixtures thereof.