Comparative study of chemically different structured sulfonic acid and sulfonimide acid of Poly(isatine-phenylene) electrolyte for PEMFC

Abstract A hydrocarbon polymer of poly (isatine-phenylene) (PiP), which was synthesized in a super acid-catalyzed polyhydroxy alkylation reaction, was introduced as an alternative conducting material in PEMFC. The sulfonimide acid in super gas-phase acidity was used to modify the sulfonic PiP (SPiP) to improve the dimensional stability and enhance proton conductivity. The PiP (SIPiP) showed considerably higher ion exchange capacity (IEC) and proton conductivity than SPiP controls. All the synthesized polymers revealed excellent thermal stability (