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 o C. 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 o C, 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 o C), which was 1.53 times higher than that of Nafion 117 (108 mS cm -1 at 80 o C). Besides, the maximum power density of SPESK-Cz-15 was 1642.7 mV cm -2 at 80 o C 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.