Grafted porous PTFE/partially fluorinated sulfonated poly(arylene ether ketone) composite membrane for PEMFC applications

A low cost and mechanically stabilized composite membrane (25 μm) based on grafted porous polytetrafluoroethylene (grPTFE) substrate and partially fluorinated sulfonated poly(arylene ether ketone) (FSPAEK) polymer was fabricated and investigated for proton exchange membrane fuel cell (PEMFC) applications. In order to improve interfacial compatibility between hydrocarbon membrane and Nafion® bonded electrode, partially fluorinated FSPAEK polymer was utilized as a proton conductor. In order to improve the combination between porous substrate and polymer, hydrophilic polystyrenesulfonate was chemically grafted onto hydrophobic PTFE substrate. The experimental results indicated that grPTFE showed richer sulfur concentration, lower water contact angle and better hydrophilicity, which made grPTFE substrate exhibit enhanced combination state with FSPAEK polymer. A relatively high mechanical stability of FSPAEK/grPTFE composite membrane was obtained and was attributed to reinforced effect of grPTFE substrate. The preliminary single cell evaluation had also confirmed FSPAEK/grPTFE composite membrane was stable. As a novel, low cost and reinforced membrane, FSPAEK/grPTFE composite membrane showed potential in PEMFC applications.