Poly(diphenylamine-co-aniline) copolymers for supercapacitor electrodes

Polyaniline, polydiphenylamine, and two copolymers with precursor monomers molar ratios of 1:1 and 3:1 (anilinium dodecyl sulfate (P1):diphenylamine) were synthesized via oxidative polymerization in a water/ethanol interfacial system. The morphology characterization and physicochemical properties showed that the copolymers share polyaniline or polydiphenylamine characteristics, depending on the monomer molar ratio. The electroactivity characterization indicated that the polydiphenylamine (PDPA) repeating units provided the copolymers with better cycling stability, whereas PAni repeating units reduced resistance and improved storage capacity, generating a synergistic interaction. Particularly, the copolymer with the highest content of P1, showed a specific capacitance of 341.93 F g(-1), with a 74.5% capacitance retention after 500 cycles, which suggests a feasible application in electrodes for supercapacitor design.