Reinforced ion-conductive membranes

• US 20070128425A1
• Filed: 12/07/2005
• Published: 06/07/2007
• Est. Priority Date: 12/07/2005
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hadj Romdhane, Ilyess, Ciliske, Scott
• Application Number:
  US11/295,764
• Publication Number:
  US 20070128425A1
• Time in Patent Office: Days
• US Class Current: 428/304.400
• CPC Class Codes: B01D 2323/60 Co-casting; Co-extrusion
• CPC Class Codes: B01D 2325/14 Membrane materials having negatively charged functional groups
• CPC Class Codes: B01D 2325/26 Electrical properties
• CPC Class Codes: B01D 2325/42 Ion-exchange membranes
• CPC Class Codes: B01D 67/0009 by phase separation, sol-gel transition, evaporation or solvent quenching
• CPC Class Codes: B01D 67/00091 by evaporation
• CPC Class Codes: B01D 67/0013 Casting processes
• CPC Class Codes: B01D 67/0016 Coagulation
• CPC Class Codes: B01D 69/1216 Three or more layers
• CPC Class Codes: B01D 69/125 In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
• CPC Class Codes: B01D 69/141 Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
• CPC Class Codes: B01D 69/1411 containing dispersed material in a continuous matrix
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: C08J 2379/08 Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: C08J 2381/06 Polysulfones; Polyethersulfones
• CPC Class Codes: C08J 5/2275 Heterogeneous membranes
• CPC Class Codes: H01M 2300/0094 in the form of layered products, e.g. coatings
• CPC Class Codes: H01M 8/1027 having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/103 having nitrogen, e.g. sulfonated polybenzimidazoles [S-PBI], polybenzimidazoles with phosphoric acid, sulfonated polyamides [S-PA] or sulfonated polyphosphazenes [S-PPh]
• CPC Class Codes: H01M 8/1032 having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/1039 : halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1048 : Ion-conducting additives, e.g. ion-conducting particles, heteropolyacids, metal phosphate or polybenzimidazole with phosphoric acid
• CPC Class Codes: H01M 8/1053 : consisting of layers of polymers with at least one layer being ionically conductive
• CPC Class Codes: H01M 8/106 : characterised by the chemical composition of the porous support
• CPC Class Codes: H01M 8/1062 : characterised by the physical properties of the porous support, e.g. its porosity or thickness
• CPC Class Codes: H01M 8/1067 : characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
• CPC Class Codes: H01M 8/1069 : characterised by the manufacturing processes
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249955 : Void-containing component partially impregnated with adjacent component
• CPC Class Codes: Y10T 428/24996 : With internal element bridging layers, nonplanar interface between layers, or intermediate layer of commingled adjacent foam layers

Abstract

An ion-conductive membrane that includes a first layer comprising a first ionomer, and a porous polymer substrate, where at least a portion of the first ionomer is interpenetrated within the porous polymer substrate by ionomer-induced phase separation.

Claims

1. An ion-conductive membrane comprising:

a first layer comprising a first ionomer; and

a porous polymer substrate, wherein at least a portion of the first ionomer is interpenetrated within the porous polymer substrate by ionomer-induced phase separation.

2. The ion-conductive membrane of claim 1, wherein the first ionomer is interpenetrated within the porous polymer substrate in a substantially uniform manner.

3. The ion-conductive membrane of claim 1, wherein the first ionomer comprises a sulfonated fluoropolymer.

4. The ion-conductive membrane of claim 1, wherein the porous polymer substrate comprises a material selected from the group consisting of polysulfones, polyether imides, and combinations thereof.

5. The ion-conductive membrane of claim 1, wherein the porous polymer substrate comprises a sulfonated porous polymer.

6. The ion-conductive membrane of claim 1, wherein the porous polymer substrate comprises a polymer having a glass transition temperature of at least about 180°

C.

7. The ion-conductive membrane of claim 1, wherein the ion-conductive membrane has a membrane thickness of about 30 micrometers or less.

8. The ion-conductive membrane of claim 7, wherein the ion-conductive membrane has a membrane thickness of about 15 micrometers or less.

9. The ion-conductive membrane of claim 1, further comprising a second layer, the second layer comprising a second ionomer, wherein at least a portion of the second ionomer is interpenetrated within the porous polymer substrate by ionomer-induced phase separation.

10. The ion-conductive membrane of claim 9, wherein the first ionomer and the second ionomer have different equivalent weights.

11. The ion-conductive membrane of claim 9, wherein the first ionomer and the second ionomer each comprise a sulfonated fluoropolymer.

12. A method of forming an ion-conductive membrane, the method comprising:

coating a first layer adjacent to a second layer, wherein the first layer comprises a first ionomer dispersed in a first solvent, and wherein the second layer comprises a reinforcement polymer substantially dissolved in a second solvent; and

initiating an ionomer-induced phase separation of the reinforcement polymer from the second solvent, thereby forming a porous polymer substrate from the reinforcement polymer and interpenetrating a portion of the first ionomer within the porous polymer substrate.

13. The method of claim 12, wherein the second layer further comprises a second ionomer.

14. The method of claim 12, wherein the step of coating the first layer adjacent to the second layer comprises coextruding the first layer and the second layer.

15. The method of claim 12, wherein the first ionomer comprises a sulfonated fluoropolymer.

16. The method of claim 12, wherein the reinforcement polymer comprises a material selected from the group consisting of polysulfones, polyether imides, and combinations thereof.

17. The method of claim 12, further comprising coating the second layer with a third layer on an opposing surface of the second layer from the first layer, the third layer comprising a second ionomer dispersed in a third solvent, wherein the ionomer-induced phase separation further interpenetrates a portion of the second ionomer within the porous polymer substrate.

25. A method comprising the step of laminating an ion-conductive membrane made according to the method of claim 12 with a second ion-conductive membrane.

18. A method of forming an ion-conductive membrane, the method comprising the steps of:

a) coating a first substrate layer having a first surface and a second surface from a first solution, the first solution comprising a reinforcement polymer substantially dissolved in a first solvent;

b) coating a first ionomer layer adjacent the first surface of the substrate layer, the first ionomer layer comprising a first ionomer;

c) coating a second ionomer layer adjacent the second surface of the substrate layer, the second ionomer layer comprising a second ionomer; and

d) initiating an ionomer-induced phase separation of the reinforcement polymer from the first solvent, thereby forming a porous polymer substrate from the substrate layer and interpenetrating a portion of the first ionomer and a portion of the second ionomer within the porous polymer substrate.

19. The method of claim 18, wherein the first substrate layer, the first ionomer layer, and the second ionomer layer are coextruded.

20. The method of claim 18, further comprising the steps of:

e) coating a second substrate layer having a first surface and a second surface from a second solution, the second solution comprising a second reinforcement polymer substantially dissolved in a second solvent;

f) coating a third ionomer layer adjacent the first surface of the second substrate layer, the third ionomer layer comprising a third ionomer;

g) coating a fourth ionomer layer adjacent the second surface of the second substrate layer, the fourth ionomer layer comprising a second ionomer;

wherein third ionomer layer is coated adjacent the second ionomer layer.

21. The method of claim 20 wherein step d) of initiating an ionomer-induced phase separation of the reinforcement polymer from the first solvent is carried out after step e) of coating a second substrate layer.

22. The method of claim 20 wherein step d) of initiating an ionomer-induced phase separation of the reinforcement polymer from the first solvent is carried out before step e) of coating a second substrate layer.

23. The method of claim 20, wherein the first substrate layer, the first ionomer layer, the second ionomer layer, the second substrate layer, the third ionomer layer, and the fourth ionomer layer are coextruded.

24. The method of claim 20, further comprising the step of:

h) initiating an ionomer-induced phase separation of the second reinforcement polymer from the second solvent, thereby forming a second porous polymer substrate from the second substrate layer and interpenetrating a portion of the third ionomer and a portion of the fourth ionomer within the second porous polymer substrate.

26. A method comprising the step of laminating an ion-conductive membrane made according to the method of claim 18 with a second ion-conductive membrane.