Abstract: A proton exchange membrane well-suited for use in a direct methanol fuel cell. According to one embodiment, the proton exchange membrane is prepared by a process comprising the steps of (a) providing a perfluorocarbon membrane, the perfluorocarbon membrane being non-permeable to water; (b) imbibing the perfluorocarbon membrane with a solution containing a styrene monomer, a divinyl benzene cross-linker, and a benzoyl peroxide activator; (c) heating the imbibed membrane to yield a cross-linked polymer within the membrane; (d) repeating the combination of steps (b) and (c) at least once; and (e) then, sulfonating the cross-linked polymer. According to another embodiment, the membrane is irradiated prior to the imbibing step, thereby rendering the membrane receptive to imbibing, polymerization, crosslinking, and grafting and obviating the need for more than one cycle of steps (b) and (c), as well as permitting step (c) to be performed at a lower temperature.

Abstract: A proton exchange membrane well-suited for use in a direct methanol fuel cell. According to one embodiment, the proton exchange membrane is prepared by a process comprising the steps of (a) providing a perfluorocarbon membrane, the perfluorocarbon membrane being non-permeable to water; (b) imbibing the perfluorocarbon membrane with a solution containing a styrene monomer, a divinyl benzene cross-linker, and a benzoyl peroxide activator; (c) heating the imbibed membrane to yield a cross-linked polymer within the membrane; (d) repeating the combination of steps (b) and (c) at least once; and (e) then, sulfonating the cross-linked polymer. According to another embodiment, the membrane is irradiated prior to the imbibing step, thereby rendering the membrane receptive to imbibing, polymerization, crosslinking, and grafting and obviating the need for more than one cycle of steps (b) and (c), as well as permitting step (c) to be performed at a lower temperature.