Effect of monomer ratio in the electrochemical synthesis of poly(aniline-co-o-methoxyaniline)

Copolymers poly(aniline-co-o-methoxyaniline) were electrosynthesized from aqueous solutions containing 1 mol l−1 HCl and a constant total concentration of monomer (0.1 mol l−1). By varying the aniline/o-methoxyaniline ratio, it was possible to observe that the electrochemical growth depends on the initial amount of o-methoxyaniline present in the solution. The UV–vis spectra show that in the doped state the copolymers containing concentration of o-methoxyaniline lower than 50% present optical absorption for λ≥1000 nm comparable to polyaniline (PAni). The conductivity measurements present a similar behavior. The infrared spectra also show a decrease of the oxidation degree with the increase of o-methoxyaniline concentration. By determining the copolymer compositions by elemental analysis, the reactivity ratios were estimated for aniline and o-methoxyaniline, and this values suggest a possible block copolymer structure.