Abstract
Summary: Polyaniline with two types of functional groups (sulfonated poly(aniline‐co‐o‐aminophenol), s‐copolymer) has been prepared by the electrochemical copolymerization of aniline and o‐aminophenol in sulfuric acid solution followed by sulfonation of the copolymer in the concentrated sulfuric acid. There are SO~3~H groups and OH groups in the s‐copolymer. The presence of SO~3~H groups on the polymer chain enables the s‐copolymer to possess intrinsic protonic doping ability. The OH group on the polymer chain can be oxidized and reduced reversibly. The shape of the cyclic voltammogram of the s‐copolymer is very similar to that of polyaniline in 0.2 M H~2~SO~4~ solution, in the potential range −0.20 to 0.80 V (vs. SCE). The results from cyclic voltammograms indicate only 22.8 and 31.6% decay of the electrochemical activity that was observed when the s‐copolymer electrode was transferred from the solution of pH 5.0 to the solutions of pH 10.0 and 11.0, respectively. Especially, there are still two pairs of redox peaks on the cyclic voltammogram of the s‐copolymer in 0.3 M Na~2~SO~4~ solution of pH 11.0 at the scan rate of 6 mV s^−1^. In this case, its usable potential range is 0.0–0.60 V. The s‐copolymer has a conductivity of 0.85 S cm^−1^, which is slightly dependent on pH when equilibrated with water. The spectra of FTIR, XPS, and ESR of the s‐copolymer are represented here.
The cyclic voltammograms of (1) poly(aniline‐co‐o‐aminophenol) and (2) s‐copolymer in H~2~SO~4~ solution.
magnified imageThe cyclic voltammograms of (1) poly(aniline‐co‐o‐aminophenol) and (2) s‐copolymer in H~2~SO~4~ solution.