Ionic functionalization of aromatic polymers for ion exchange membranes
The electrochemical energy conversion system of the present disclosure includes an anode, a cathode, and an ion exchange membrane including a polymer having an aromatic polymer chain and an alkylated substrate including an alkyl chain, and at least one ionic group. The alkylated substrate is bound to at least one aromatic group in the polymer chain via Friedel-Crafts alkylation of the at least one aromatic group. The alkylation reaction utilizes a haloalkylated tertiary alcohol or a haloalkylated alkene as a precursor. In the presence of an acid catalyst, a carbocation is generated in the precursor which reacts with the aromatic rings of the polymer chain. The at least one ionic group is then replaced with a desired cationic or anionic group using a substitution reaction. The membranes exhibit advantageous stability achieved through a simplified and scalable reaction scheme.
1. A polymer according to formula IV:
wherein Ar is an aryl;
Z is selected from the group consisting of O, S, CH 2 , and C 6 H 4 ;
R is an alkyl;
FG comprises a moiety selected from the group consisting of an alkyl, an aryl, OH, a sulfonate, a phosphonate, and a quaternary ammonium group, wherein at least one FG comprises an ionic moiety;
EW comprises a moiety selected from the group consisting of an electron-withdrawing group, CF 3 , a nitrile, a pyridine, a heterocyclic amine, —C═O, and an amide;
x is from 1 to 20;
n and m are each independently from 100 to 1,000,000.
2. The polymer of claim 1 , wherein the polymer is an anion exchange polymer.
3. The polymer of claim 1 , wherein at least one FG comprises a quaternary ammonium group.
4. The polymer of claim 1 , wherein at least one FG comprises (CH 2 ) x ·N + R 1 R 2 R 3 , wherein R 1 , R 2 , and R 3 is each an alkyl.
5. The polymer of claim 4 , wherein R 1 , R 2 , and R 3 is each methyl.
6. The polymer of claim 4 , wherein EW is CF 3 .
7. The polymer of claim 1 , wherein Ar includes
or combinations thereof.
8. The polymer of claim 1 , wherein the polymer has formula V
9. The polymer of claim 1 , wherein the polymer is a cation exchange polymer.
10. The polymer of claim 1 , wherein at least two FGs in a repeating unit comprise an ionic moiety.
11. The polymer of claim 1 , wherein at least three FGs in a repeating unit comprise an ionic moiety.
12. A polymer according to formula VI:
wherein Ar is an aryl;
R is an alkyl;
EW comprises a moiety selected from the group consisting of an electron-withdrawing group, CF 3 , a nitrile, a pyridine, a heterocyclic amine, —C═O, and an amide;
x is from 2 to 20;
n and m are each independently from 100 to 1,000,000.
13. The polymer of claim 12 , wherein EW is CF 3 .
14. The polymer of claim 12 , wherein Ar includes
or combinations thereof.
15. The polymer of claim 12 , wherein the polymer has formula VII:
16. A polymer according to formula VIII
wherein GC is a graft chain comprising multiple ionic moieties;
wherein Ar is an aryl;
R is an alkyl;
EW comprises a moiety selected from the group consisting of an electron-withdrawing group, CF 3 , a nitrile, a pyridine, a heterocyclic amine, —C═O, and an amide;
n and m are each independently from 100 to 1,000,000.
17. The polymer of claim 16 , wherein the multiple ionic moieties include multiple quaternary ammonium groups.
18. The polymer of claim 16 , wherein EW is CF 3 .
19. The polymer of claim 16 , wherein Ar includes
or combinations thereof.
20. The polymer of claim 16 , wherein R is an alkyl and EW is CF 3 .