Sulfonated-polyperfluoro-cyclobutane-polyphenylene polymers for PEM fuel cell applications
View Patent ↗A polymer for ion conductor applications includes a polymer segment having a perfluorocyclobutyl moiety and a polymer segment not having such a moiety. One of these polymer segments is sulfonated to improve ionic conductivity. Fuel cells incorporating the ion conducting polymers are provided.
1. A polymer comprising polymer segments 1 and 2:
E 1 (Z 1 ) d —P 1 -Q 1 -P 2 [1]
E 2 (Z 1 ) f —P 3 [2]
wherein:
Z 1 is —SO 2 X, —PO 3 H 2 , or —COX;
E 1 , E 2 is an aromatic or aliphatic-containing moiety wherein at least one of E 1 and E 2 include an aromatic substituted with Z 1 ;
X is an —OH, a halogen, an ester, or
d is the number of Z 1 functional groups attached to E 1 ;
f is the number of Z 1 functional groups attached to E 2 ;
P 1 , P 2 , and P 3 are each independently absent, —O—,—S—, —SO—,—SO 2 , —CO—, —NH—, NR 2 —, or —R 3 —, and
R 2 is C 1-25 alkyl, C 1-25 aryl or C 1-25 arylene;
R 3 is C 1-25 alkylene, C 1-25 perfluoroalkylene, perfluoroalkyl ether, alkyl ether, or C 1-25 arylene;
R 4 is trifluoromethyl, C 1-25 alkyl, C 1-25 perfluoroalkylene, C 1-25 aryl, or another E 1 group; and
Q 1 is a fluorinated cyclobutyl moiety,
with the proviso that when d is greater than zero, f is zero; and when f is greater than zero, d is zero.
2. The polymer of claim 1 wherein Q 1 and Q 2 are each independently a perfluorocyclobutyl moiety.
3. The polymer of claim 1 wherein Q 1 and Q 2 are each independently:
4. The polymer of claim 1 wherein polymer segments 1 and 2 are repeated to form polymer units 3 and 4:
wherein:
i is a number representing repetition of polymer segment 1 to define polymer unit 3; and
j is a number representing repetition of a polymer segment 2 to define polymer unit 4.
5. The polymer of claim 4 wherein i and j are each independently from 1 to 500.
6. The polymer of claim 4 wherein i and j are each independently from 1 to 200.
7. The polymer of claim 3 wherein polymer units 3 and 4 are linked to form one or both of the following polymer units:
where L 1 is absent or a linking group.
8. The polymer of claim 7 wherein segments 7 and 8 are repeated to form:
where L 2 is absent or a linking group and k is an integer number representing repetition of the polymer segment 3.
9. The polymer of claim 8 wherein L 1 and L 2 each independently comprise an ether, imide, amide, ester, amine, ketone or acyl groups.
10. The polymer of claim 8 wherein L 1 and L 2 each independently comprise a chemical structure represented by one of the following formulae:
where R 5 is an organic group, such as an alkyl or acyl group.
11. The polymer of claim 1 wherein E 1 and E 2 each independently comprises a structural unit represented by one of the following formulas:
12. The polymer of claim 1 wherein E 1 and/or E 2 comprises a structural unit represented by one of the following formulas:
13. The polymer of claim 1 wherein Z 1 is present at about 1 meq/g or greater.
14. The polymer of claim 1 wherein E 1 comprises at least one phenyl or phenylene group to which Z 1 is directly attached.
15. The polymer of claim 1 wherein E 1 (Z 1 ) d or E 2 (Z 1 ) f comprises a structure unit represented by one of the following formulae:
where n is a positive integer.