Shifting the degree of sulfonation in a polyaniline derivative by the applied potential

Diphenylamine-4-sulfonic acid and aniline were copolymerized by cyclic scanning of the potential in 1 M HCl solutions on platinum substrates. The inversion potential was shifted from values where diphenylamine-4-sulfonic acid is the only monomer oxidized to higher values where the oxidation of aniline is significant. FTIR-ATR spectroscopy and XPS results revealed the role played by the inversion potential on the preferential incorporation of each monomer. As a result, the sulfonation degree of the copolymers shows an interesting influence of the upper potential limit employed.