Redox interaction of sulfonated polyaniline with vanadium(IV) in water

The redox interaction between poly(2-methoxyaniline-5-sulfonic acid) (PMAS, emeraldine form) and V(IV) readily occurred to produce the PMAS(red) and V(V) species in an aqueous solution. Notably, molecular oxygen was able to reoxidize PMAS(red) to form the catalytic redox cycle. This redox interaction was effectively observed in basic conditions rather than in acidic ones.