The effects of reaction time on the electrochemical properties (cyclic voltammogram, electrochemical impedance spectroscopy and Tafel curve) of polyaniline (PAn) synthesized by emulsion polymerization were investigated for the first time by using the carbon paper loaded PAn as working electrode, and the characterization result of the electrochemical properties of the PAn was proved by the contrast analysis of the conductivity, the yield and the intrinsic viscosity of the PAn. The experimental results showed that there were three pairs of characteristic redox peaks of the PAn in the cyclic voltammetry and a nearly complete semi-circle in the impedance. Moreover, the cyclic voltammetry, the impedance, the Tafel curve, the yield and the conductivity of the PAn had a similar trend with the change of reaction time. The PAn with good properties was obtained when the reaction time was 5 h. It is suggested that the electrochemical property of the PAn synthesized by emulsion polymerization can be real-time characterized efficiently by using the carbon paper loaded PAn as working electrode.

Key words: polyaniline, carbon paper, electrode, electrochemical property