Synthesis of Sulfonated Poly(Arylene Ether Sulfone)s Containing Aliphatic Moieties for Effective Membrane Electrode Assembly Fabrication by Low-Temperature Decal Transfer Methods.

The purpose of this study was to investigate the effect of the aliphatic moiety in the sulfonated poly(arylene ether sulfone) (SPAES) backbone. A new monomer (4,4'-dihydroxy-1,6-diphenoxyhexane) was synthesized and polymerized with other monomers to obtain partially alkylated SPAESs. According to differential scanning calorimetry analysis, the glass transition temperature (Tg) of these polymers ranged from 85 to 90 °C, which is 100 °C lower than that of the fully aromatic SPAES. Due to the low Tg values obtained for the partially alkylated SPAESs, it was possible to prepare a hydrocarbon electrolyte membrane-based membrane electrode assembly (MEA) with Nafion® binder in the electrode through the use of a decal transfer method, which is the most commercially suitable system to obtain an MEA of proton exchange membrane fuel cells (PEMFCs). A single cell prepared using this partially alkylated SPAES as an electrolyte membrane exhibited a peak power density of 539 mW cm-2.