Multi-acid polymers from multifunctional amino acids and sulfonyl halide precursors and methods of making the same
Multi-acid polymers are produced having the formula R—SO 2 —NH—R′—(SO 3 H) n and made from a polymer precursor in sulfonyl fluoride form or sulfonyl chloride form The R is one or more units of the polymer precursor without sulfonyl fluoride or sulfonyl chloride, R′ is the portion of the amino sulfonic acid without the SO 3 H and NH, n is one or more, and the multi-acid polymer has two or more proton conducting groups. A method of making the multi-acid polymers includes reacting an amino acid having multiple sulfonic acids with a polymer precursor in sulfonyl fluoride form or sulfonyl chloride form in a mild base condition to produce the multi-acid polymer having two or more proton conducting groups.
1. A multi-acid polymer having the formula R—SO 2 —NH—R′—(SO 3 H) n , and made from an amino sulfonic acid and a polymer precursor in sulfonyl fluoride form or sulfonyl chloride form, R′ is the portion of the amino sulfonic acid without the SO 3 H and NH, n is one or more, the multi-acid polymer has two or more proton conducting groups, R is:
and wherein R f ═—CF 2 —CF(CF 3 )—O—(CF 2 ) 2 —, —(CF 2 ) 4 —, or —(CF 2 ) 2 —, m=3-13.5, n=1 or more.
2. The multi-acid polymer of claim 1 , the multi-acid polymer has four proton conducting groups and the following formula:
wherein n=3.
3. The multi-acid polymer of claim 1 , wherein the polymer precursor is a fluorinated polymer or resin or membrane in sulfonyl fluoride form.
4. The multi-acid polymer of claim 1 , wherein the polymer precursor is selected from the following group: 2-allyloxy-1,1,2,2-tetrafluoro ethane sulfonyl fluoride, 4-(trifluoro vinyl) benzene sulfonyl fluoride, and p-styrene sulfonyl fluoride.
5. The multi-acid polymer of claim 1 , wherein the polymer precursor is perfluoro (3-oxapent-4-ene) sulfonyl fluoride.
6. The multi-acid polymer of claim 1 , wherein the polymer precursor is ethene sulfonyl fluoride.
7. The multi-acid polymer of claim 1 , wherein the polymer precursor is 2-propene-1-sulfonyl chloride or p-styrene sulfonyl chloride.
8. The multi-acid polymer of claim 1 , wherein the polymer precursor is perfluoro(4-methyl-3,6-dioxaoct-7-ene)sulfonyl fluoride.
9. A multi-acid membrane for a fuel cell comprising the multi-acid polymer of claim 1 .