High efficiency of proton transport by clustering nanochannels in multi-sulfonated propeller-like nonplanar hexaphenylbenzene poly(ether sulfone)s

The propeller-like nonplanar building unit containing poly(aryl ether ketone)s were synthesized from 1,2-bis(4-hydroxyphenyl)-3,4,5,6-tetraphenyl-benzene (BHPTPB) and bis(4-fluorophenyl) sulfone with bis(4-hydroxydiphenyl) sulfone in NMP. New structures and/or morphologies for existing materials need to be considered in case if increased benefits are desired. The sulfonation was taken selectively on hydrophilic block segment as well as para position of the pendent phenyl groups with concentrated sulfuric acid. The stoichiometry mole ratios were changed with hydrophilic blocks of 12, 15, 17, 20, and 23 mol% of BHPTPB monomer to control the ion exchange capacity. The structural properties of polymer membranes (HP-12, 15, 17, 20, and 23) were studied by FT-IR, 1H NMR spectroscopy, thermogravimetric analysis (TGA), and atomic force microscope (AFM). The water uptakes were 8.1-69.4% at 75 °C with changing the ion exchange capacities. The resulted proton conductivities were 66.58-103.73 mS/cm at 80 °C with 90% relative humidity. The highest power density of a fuel cell using HP-23 and Nafion 211 was 0.47 and 0.45 W/cm2, respectively, at 0.6 V.