PEMFC is an eco-friendly and sustainable electrochemical generation system to convert chemical energy of fuels into electric energy. Proton exchange membrane(PEM) is key material to decide PEMFC performances. Representative PEM materials is perfluorinated sulfonic acid(PFSA) composed of a chemically stable PTFE backbone and ion conductive side chains. PFSA is classified into long-side chain(LCC-PFSA) and short-side chain(SCC-PFSA). Normally, SCC-PFSA can induce high packing density and gas barrier properties when it is made in PEM state. In spite of these advantages, it is hard to make desirable SCC-PFSA PEMs due to its relatively high Tg and low EW. In this study, the effects of PEM fabrication histories on basic properties of SCC-PFSA ionomers were observed by varying parameters such as casting solvent and thermal annealing condition.

Perfluorinated sulfonic acid (PFSA) ionomers have been widely used as membranes in the fields of green power generation and electrolysis. In spite of their high ion-conducting properties, it is difficult to apply them in the freestanding membrane state to harsh operation conditions owing to their chemical and electrochemical degradation issues. A promising membrane concept to satisfy this purpose would be “pore-filling membrane” composed of PFSA ionomers and porous PTFE support films. In this study, the porous PTFE support film treated with a cheap hydrophilic polymer is used as a reinforced material. Interestingly, the resulting PFSA-PTFE pore-filling membranes exhibit an extremely high proton conductivity with a fairly reduced ionomer content, which may give a valuable information to design a desirable pore-filling membrane.