Electrolyte membrane, methods of manufacture thereof and articles comprising the same

1. A method of forming an electrolyte membrane comprising:

forming a monomer mixture; the mixture comprising a polyhydroxy compound, an aromatic polyhalide compound and an alkali metal hydroxide;

disposing the mixture on a porous substrate;

reacting the mixture to form a crosslinked proton conductor; and sulfonating the proton conductor.

2. The method of claim 1 , wherein the aromatic polyhalide compound is an aromatic sulfonated dihalide.

3. The method of claim 1 , wherein the polyhydroxy compound is a compound having a structure shown in Formula (I):

wherein B is a hydrogen, alkyl, aryl or a protonic acid containing group; the protonic acid group being a sulfonate group (—SO 3 H), a carboxylate group (—COOH), a phosphate group (—PO 3 H 2 ), an alkylsulfonate group —(R 4 ) n SO 3 H), a sulfamoylsulfonylalkyl group or a sulfamoylsulfonylaryl group (—SO 2 NHSO 2 R) where R is alkyl or aryl, a perfloruoalkylsulfonate group (CF 2 ) n SO 3 H), a sulfonylalkylsulfonate group (SO 2 (R 4 ) n SO 3 H), a sulfonylperfluoroalkylsulfonate group (SO 2 (CF 2 )SO 3 H), a sulfamoylsulfonylalkylsulfonate group (SO 2 NHSO 2 (R 4 ) n SO 3 H), a sulfamoylsulfonylperfluoroalkylsulfonate group (SO 2 NHSO 2 (CF 2 ) n SO 3 H), an alkylcarboxylate group (—(R 4 ) n COOH), a perfluoroalkylcarboxylate group (CF 2 ) n CO 2 H an alkylphosphonate group (—(R 4 ) n PO 3 H 2 ), a perfluoroalkylphoshonate group or their conjugated salts; the conjugated salts having a metal cation; R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-50 aryl group; q and r are independently integers from 1 to about 4; R 4 is an alkyl, aryl or perfluoroalkyl group, X is O, S, or SO 2 , and W is selected from the group consisting of

—SO 2 NHSO 2 —, —SO 2 (CF 2 ) n SO 2 — and a benzoxazole having the formula below:

wherein R c and R d each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group, and R e is a divalent hydrocarbon group, oxygen, or sulfur and wherein the benzoxazole is optionally substituted with at least one of a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-50 aryl group, or a halogen-substituted C 6-50 aryl group and wherein n is from about 1 to about 10.

4. The method of claim 1 , wherein the polyhydroxy compound has a structure shown in Formula (II) below:

where R 5 , R 6 , R 7 and R 8 are each independently a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-50 aryl group or a halogen-substituted C 6-50 aryl group, and n, o and p are each independently integers of 1 to about 4.

5. The method of claim 1 , wherein the aromatic polyhalide compound has a structure shown in Formula (III):

where X is a halogen, R 9 and R 10 are each independently a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-10 aryl group, or a halogen-substituted C 6-10 aryl group, s and t are each independently integers of 1 to 4, R 11 represents one of the following groups

—SO 2 NHSO 2 —, —SO 2 (CF 2 ) n SO 2 — or

and C in Formula (III) is a protonic acid containing group; the protonic acid containing group being a sulfonate group (—SO 3 H), a carboxylate group (—COOH), a phosphate group (—PO 3 H 2 ), an alkylsulfonate group (—(R 12 ) n SO 3 H), a sulfamoylsulfonylalkyl or sulfamoylsulfonylaryl group (—SO 2 NHSO 2 R), wherein R is alkyl or aryl), a perfloruoalkylsulfonate group (CF 2 ) n SO 3 H), a sulfonylalkylsulfonate group (SO 2 (R 12 ) n SO 3 H), a sulfonylperfluoroalkylsulfonate group (SO 2 (CF 2 )SO 3 H), a sulfamoylsulfonylalkylsulfonate group (SO 2 NHSO 2 (R 12 ) n SO 3 H), a sulfamoylsulfonylperfluoroalkylsulfonate group (SO 2 NHSO 2 (CF 2 ) n SO 3 H), an alkylcarboxylate group (—(R 12 ) n COOH), a perfluoroalkylcarboxylate group (CF 2 ) n CO 2 H, an alkylphosphonate group (—(R 12 ) n PO 3 H 2 ), an perfluoroalkylphoshonate group or their conjugated salts; the conjugated salts having a metal cation and wherein R 12 can be an alkyl, aryl or perfluoroalkyl group and n is from about 1 to about 10.

6. The method of claim 1 , wherein the aromatic polyhalide compound has the structure shown in Formula (IV):

where X is a halogen and R 13 and R 14 are each independently a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-10 aryl group, or a halogen-substituted C 6-10 aryl group; q and r are each independently integers of 1 to 3, R 15 represents one of the following groups:

—SO2NHSO2—, —SO2(CF2)nSO2— or

wherein R c and R d each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group, and R e is a divalent hydrocarbon group, oxygen, or sulfur, q and r are each independently integers of 1 to 3, M represents a metal cation from Group I.

7. The method of claim 6 , wherein R 13 and R 14 are each independently a hydrogen atom or a halogen atom, M is sodium, X is fluorine, and q and r are each independently integers of 1 to 3.

8. The method of claim 1 , further comprising adding a first solvent to the mixture.

9. The method of claim 1 , further comprising adding a second solvent to the mixture, wherein the second solvent is selected from the group consisting of an alcohol, water, liquid carbon dioxide, an aldehyde, a ketone, a nitrile, a sulfoxide, a sulfone, an ester, an amide, and a combination comprising at least one of the foregoing solvents.

10. The method of claim 9 , wherein the second solvent is selected from the group consisting of isopropyl alcohol, dimethylsulfoxide, and a combination comprising at least one of the foregoing solvents.

11. The method of claim 1 , wherein the porous substrate comprises an organic polymer selected from the group consisting of polyolefins, polyamides, polycarbonates, cellulosic polymers, polyurethanes, polyesters, polyethers, polyacrylates, copolyether esters, copolyether amides, chitosan, fluoropolymers, and a combination comprising at least one of the foregoing organic polymers.

12. The method of claim 1 , wherein the porous substrate comprises a fluoropolymer selected from the group consisting of polytetrafluoroethylene, poly(vinylidene fluoride), poly(vinylidene fluoride-co-hexafluoropropylene), poly(tetrafluoroethylene oxide-co-difluoromethylene oxide, poly(tetrafluoroethylene-co-perfluoro(propylvinyl ether)), and a combination comprising at least one of the foregoing fluoropolymers.

13. The method of claim 12 , wherein the fluoropolymer is expanded polytetrafluoroethylene.

14. The method of claim 1 , further comprising reacting the mixture to form a proton conductor before disposing the mixture on the porous substrate.

15. The method of claim 1 , wherein the mixture is disposed by extrusion, brushing, spraying, transfer coating, or a combination comprising at least one of the foregoing coating methods.

16. The method of claim 1 , further comprising wherein the proton conductor is formed within and between the pores of the porous substrate to form a cross-linked proton-conducting network integrated with the porous substrate.

17. The method of claim 1 , wherein the electrolyte membrane comprises about 0.5 weight percent to about 50 weight percent proton conductor, based on the total weight of the electrolyte membrane.

18. The method of claim 1 , wherein the electrolyte membrane has a proton conductivity of greater than about 0.0001 Siemens per centimeter at about 80° C. and about 50 percent relative humidity.

19. A method comprising:

deprotonating a tris(hydroxyphenyl)ethane to produce a deprotonated tris(hydroxyphenyl)ethane;

reacting the deprotonated tris(hydroxyphenyl)ethane with sulfonated difluorodiphenylsulfone in the pores of a porous substrate to produce cross-linked polyethersulfone as shown in the reaction (I)

sulfonating the crosslinked polyethersulfone as shown in the reaction (II)

to produce a sulfonated crosslinked polyethersulfone in the pores of the porous substrate.

20. The method of claim 19 , wherein the tris(hydroxyphenyl)ethane is deprotonated with an alkali metal hydroxide.

21. The method of claim 19 , wherein the porous substrate comprises a fluoropolymer selected from the group consisting of polytetrafluoroethylene, poly(vinylidene fluoride), poly(vinylidene fluoride co-hexafluoropropylene), poly(tetrafluoroethylene oxide-co-difluoromethylene oxide, poly(tetrafluoroethylene-co-perfluoro(propylvinyl ether)), and a combination comprising at least one of the foregoing fluoropolymers.

22. A method of forming an electrolyte membrane comprising:

forming a first mixture, the mixture comprising a first solvent, an alkali metal hydroxide and a compound of formula (V):

where R 16 , R 17 and R 18 are each a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-10 aryl group, or a halogen-substituted C 6-10 aryl group and n, o and p are each independently integers of 1 to about 4;

heating the first mixture;

adding to the first mixture a compound of formula (VI):

where X is a halogen and R 19 and R 20 are each independently a hydrogen atom, a halogen atom, a C 1-10 alkyl group, a halogen-substituted C 1-10 alkyl group, a C 6-10 aryl group, or a halogen-substituted C 6-10 aryl group, and q and r are each independently integers of 1 to 3;

adding to the first mixture a second solvent to form a second mixture, wherein the second solvent comprises isopropanol and dimethylsulfoxide;

disposing the second mixture on a porous substrate, the porous substrate comprising expanded polytetrafluoroethylene;

reacting the second mixture to form a crosslinked proton conductor integrated with the porous substrate to form an electrolyte membrane; and

sulfonating the crosslinked proton conductor with a sulfonating agent for form a sulfonated crosslinked proton conductor.