Ion conducting polymer membranes
Modified ion-conducting membranes ( 10 ), and a method for making the same, which increases the membrane ( 10 ) surface area, and, optionally, incorporates mono- and multi-metal ion-containing catalysts for both fuel consumption catalysis in fuel cells as well as catalysis of reactions to ameliorate the effects of CO and other impurities in fuel cells. The membranes ( 10 ) modified by these methods can fin application in catalysis and transport applications.
1. A method for forming an ion conducting polymer membrane having a deformed surface area exceeding the membrane's cross-sectional area by at least 20%, said method comprising the steps of:
providing an ion conducting polymer membrane ( 10 );
at least partially dehydrating said membrane ( 10 ); and
applying a voltage across said membrane ( 10 ) sufficient to generate surface deformation on said membrane.
2. A method according to claim 1 , wherein said step of at least partially dehydrating said membrane ( 10 ) is performed such that said membrane ( 10 ) has a water content of from about 2% to about 15% by weight after said step is completed.
3. A method according to claim 1 , wherein said step of applying a voltage across said membrane ( 10 ) is performed by applying a voltage of from about 20 to about 800 volts for a period of about 5 to about 120 minutes.
4. A method according to claim 1 , wherein said step of applying a voltage across said membrane ( 10 ) is performed by placing said membrane between an anode ( 12 ) and a cathode ( 14 ) connected by a voltage source.
5. A method according to claim 1 , wherein said step of at least partially dehydrating said membrane ( 10 ) is performed such that the ratio of H 2 O molecules to H + in said membrane ( 10 ) is from about 1.5 to about 9 after said step is completed.
6. A method according to claim 1 , wherein said step of at least partially dehydrating said membrane ( 10 ) is performed by subjecting said membrane ( 10 ) to a vacuum for an effective amount of time.
7. A method according to claim 6 , wherein said step of at least partially dehydrating said membrane ( 10 ) is performed by placing said membrane ( 10 ) in a chamber and evacuating said chamber at about 1×10 −3 torr pressure at about 25° C. for about 24 hours.
8. A method according to claim 1 , wherein said step of applying a voltage across said membrane is performed by placing said membrane between an anode ( 12 ) and a cathode ( 14 ) connected to a voltage source.
9. A method according to claim 8 , wherein said surface deformation is formed on said membrane at a surface of said membrane adjacent said anode ( 12 ).