ePTFE-Supported Polyelectrolyte Membranes Made with Ionomer-Kynar Blends
A composite membrane for fuel cells includes an expanded polytetrafluoroethylene substrate having a predefined void volume, a first polymer and a second polymer each of which fill at least a portion of the void volume. The first polymer includes the following chemical moiety: Polymer electrolyte membranes and fuel cells incorporating the composite membrane are also provided.
1 . A composite membrane for fuel cells, the composite membrane comprising:
an expanded polytetrafluoroethylene substrate having a predefined void volume;
a first polymer having a chemical moiety described by formula (I):
and
a second polymer including a nonionic polymer wherein the first polymer and second polymer each fill at least a portion of the void volume.
2 . The composite membrane of claim 1 wherein the first polymer is a perfluorosulfonic acid polymer (PFSA).
3 . The composite membrane of claim 1 wherein the first polymer is a copolymer containing repeating units based on tetrafluoroethylene and repeating units represented by (CF 2 —CF)—(OCF 2 CFX) m —O p —(CF 2 ) n —SO 3 H, where X represents a fluorine atom or a trifluoromethyl group, m represents an integer from 0 to 3, n represents an integer from 1 to 12 and p represents an integer of 0 or 1.
4 . The composite membrane of claim 3 wherein m=1, X=CF 3 , p=1, and n=2.
5 . The composite membrane of claim 3 wherein m=0, p=1, and n=2.
6 . The composite membrane of claim 3 wherein m=0, p=1, and n=4.
7 . The composite membrane of claim 1 wherein the first polymer comprises a polymer selected from the group of polymers having the following formulae:
where o, p, n, are integers such that there are less than 15 o segments for each p segment.
8 . The composite membrane of claim 1 wherein the second polymer comprises fluoropolymers.
9 . The composite membrane of claim 8 wherein the second polymer comprises a fluoro-elastomer.
10 . The composite membrane of claim 8 wherein the second polymer comprises a component selected from the group consisting of poly(tetrafluoroethlyene-co-ethylene), poly(vinylidene fluoride-co-hexafluoropropylene), poly(tetrafluoroethylene-co-propylene), terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, and terpolymers of ethylene, tetrafluoroethylene and perfluoromethylvinylether.
11 . A composite membrane for fuel cells, the composite membrane comprising:
an expanded polytetrafluoroethylene substrate having a predefined void volume;
a first polymer comprising a copolymer containing repeating units based on tetrafluoroethylene and repeating units represented by (CF 2 —CF)—(OCF 2 CFX) m —O p —(CF 2 ) n —SO 3 H, where X represents a fluorine atom or a trifluoromethyl group, m represents an integer from 0 to 3, n represents an integer from 1 to 12 and p represents an integer of 0 or 1; and
a second polymer comprising a fluoropolymer wherein the first polymer and second polymer each fill at least a portion of the void volume.
12 . The composite membrane of claim 11 wherein m=1, X=CF 3 , p=1, and n=2.
13 . The composite membrane of claim 12 wherein m=0, p=1, and n=2.
14 . The composite membrane of claim 12 wherein m=0, p=1, and n=4.
15 . The composite membrane of claim 11 wherein the second polymer comprises a fluoro-elastomer.
16 . The composite membrane of claim 11 wherein the fluoropolymer comprises a component selected from the group consisting of poly(tetrafluoroethlyene-co-ethylene), poly(vinylidene fluoride-co-hexafluoropropylene), poly(tetrafluoroethylene-co-propylene), terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, and terpolymers of ethylene, tetrafluoroethylene and perfluoromethylvinylether.
17 . A polymer electrolyte membrane for fuel cells, the polymer electrolyte membrane comprising:
a composite membrane having a first side and a second side, the composite membrane including:
an expanded polytetrafluoroethylene substrate having a predefined void volume;
a first polymer having a chemical moiety described by formula (I):
and
a second polymer including a non-ionic fluoropolymer wherein the first polymer and second polymer each fill at least a portion of the void volume;
a cathode disposed on the first side; and
an anode disposed on the second side.
18 . The polymer electrolyte membrane of claim 17 wherein the first polymer is a copolymer containing repeating units based on tetrafluoroethylene and repeating units represented by (CF 2 —CF)—(OCF 2 CFX) m —O p —(CF 2 ) n —SO 3 H, where X represents a fluorine atom or a trifluoromethyl group, m represents an integer from 0 to 3, n represents an integer from 1 to 12 and p represents an integer of 0 or 1.
19 . The polymer electrolyte membrane of claim 17 wherein the second polymer comprises a component selected from the group consisting of poly(tetrafluoroethlyene-co-ethylene), poly(vinylidene fluoride-co-hexafluoropropylene), poly(tetrafluoroethylene-co-propylene), terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, and terpolymers of ethylene, tetrafluoroethylene and perfluoromethylvinylether.