Sulfonated polyphenylene polymers
Improved sulfonated polyphenylene compositions, improved polymer electrolyte membranes and nanocomposites formed there from for use in fuel cells are described herein. The improved compositions, membranes and nanocomposites formed there from overcome limitations of Nafion® membranes.
1. A sulfonated polyphenylene polymer, derived by controllably sulfonating a polyphenylene polymer with a sulfonating agent, the sulfonated polyphenylene polymer having repeat units of the following structure 1:
in which
R 1 , R 2 and R 3 are the same or different, wherein each R 1 , R 2 , and R 3 is H or an unsubstituted or inertly-substituted aromatic moiety;
Ar 1 and Ar 2 are the same or different, wherein each Ar 1 and Ar 2 is an unsubstituted aromatic moiety or inertly-substituted aromatic moiety;
wherein a pendant side chain of a sulfonyl group attaches to a carbon atom;
wherein from one to six sulfonyl groups are attached per repeat unit;
wherein n≦2; and
wherein any combination of R 1 , R 2 and R 3 and Ar 1 and Ar 2 comprises a sub-combination selected from the group consisting of:
a) R 1 is different than R 2 ,
b) R 1 is different than R 3 ,
c) R 2 is different than R 3 ,
d) Ar 1 is different than Ar 2 , and
e) R 1 ═R 2 ═R 3 ═Ar 1 ═Ar 2 .
2. The sulfonated polyphenylene polymer of claim 1 , wherein R 1 ═R 2 ═R 3 ═Ar 1 ═Ar 2 =phenyl.
3. The sulfonated polyphenylene polymer of claim 1 , wherein R 1 ═R 2 ═Ar 1 ═Ar 2 =phenyl, and R 3 ═H.
4. The sulfonated polyphenylene polymer of claim 1 , wherein n ranges from about 130 to 300.
5. The sulfonated polyphenylene polymer of claim 1 , wherein the sulfonyl groups are homogenously distributed in the polymer.
6. The sulfonated polyphenylene polymer of claim 1 , wherein the polymer has a proton conductivity at 25° C. of about 10 mS/cm to about 125 mS/cm.
7. The sulfonated polyphenylene polymer of claim 1 , wherein each aromatic moiety comprises a phenyl, a polyaromatic, or a fused aromatic moiety that is unsubstituted or inertly-substituted.
8. The sulfonated polyphenylene polymer of claim 7 , wherein each aromatic moiety is selected from the group consisting of:
where each Z is selected from —O—, —S—, alkylene, —CF 2 —, —CH 2 —, —O—CF 2 —, perfluoroalkyl, perfluoroalkoxy,
where R 5 is selected from —H, —CH 3 , —CH 2 CH 3 , —(CH 2 )CH 3 , or Ph; and
wherein x=CH 3 , CEt 3 , CMe 3 , CF 3 , NMe 2 , NH 2 , F, Cl, Br, OCH 3 , OH, OCF 3 , O-Ph, Ph, and SO 3 R 5 .