Synthesis and properties of novel poly(arylene ether)s with densely sulfonated units based on carbazole derivative

The advancement of proton conductive applications will require the identification of new membrane with high-conductivity and good dimensional stability that can be readily obtained and cheap. We reported a novel rigid carbazole derivative and proton exchange membrane consisting of densely sulfonated carbazole derivative, which could form aggregated ionic cluster of sulfonic acid group and result in continuous broad-dimensional nanochannels. The SAXS analysis confirmed these copolymers owned large ion clusters. All of membranes prepared in this work were thermally stable at up to 250 oC. These membranes also exhibited excellent dimensional stability and outstanding proton conductivity. SPESK-Cz-15 with IEC = 2.07 meq g-1 showed the largest water uptake with a value of 107%, but the swelling ratio was only 36.4% at 100 oC, which was attributed to the artful structure of the copolymers. SPESK-Cz-15 showed very high proton conductivity (165.3 mS cm-1 at 80 oC), which was 1.53 times higher than that of Nafion 117 (108 mS cm-1 at 80 oC). Besides, the maximum power density of SPESK-Cz-15 was 1642.7 mV cm-2 at 80 oC under 95% RH. The stability of single cell based on SPESK-Cz-15 was remarkable. All above indicate that SPESK-Cz-x are potential materials for polymer electrolyte membrane fuel cells in the future.