Polymer, Vol.160, 138-147, 2019
Multidirectional proton-conducting membrane based on sulfonated big pi-conjugated monomer into block copoly(ether sulfone)s
The R&D of proton exchange membrane (PEM) with high conductivity and excellent stability is still of significance for the next generation high power density PEM fuel cells. One irreconcilable challenge is that the high proton conductivity realized through high ion exchange capacity (IEC) strategy always gets along with poor membrane stability. To alleviate this contradiction, large-size planar 4,4'-(5,11-dihydroindolo [3,2-b] carbazole-6,12-diyl)diphenol (DCP) units with highly dense sulfonation were deliberately incorporated into block poly (ether sulfone)s to facilitate the formation of hydrophobic/hydrophilic nanophase-separated structure and multidirectional proton-conducting channels through strong intermolecular pi-pi interaction and ionic acid-base interaction. In fact, proton conductivity of our PEMs with an IEC of 1.52 mequiv g(-1) is up to 248.2 mS cm(-1) at 90 degrees C without compromising its mechanical properties. The novel multi-sulfonated poly(ether sulfone)s could give a guideline for the development of multidirectional proton-conducting membrane.