Abstract: Electroactive polyaniline (PAN) thin films were synthesized on platinum substrates by electrochemical polymerization, the electrochemical quartz crystal microbalance (EQCM) technique was adopted to investigate the polymerization process of the PAN film and its redox behavior in phenol solution. Combined with cyclic voltammetry (CV), electroactivity and stability of the PAN film cycled between the reduced, leucoemeraldine (L) state and the half-oxidized, emeraldine (E) state or between L and the fully oxidized, pemigraniline (P) state were investigated in 0.5 mol/L H2SO4 solution. In mixed solutions of phenol and H2SO4, chronocoulometry and FT-IR were also used to investigate the electrochemically controlled phenol separation property of PAN film. Experimental results indicate that the abrupt changes of the film mass exist during the redox switching of PAN with the ion ejection/injection, especially with the increase of the films thickness; and PAN films have good electroactivity and stability when films are controlled between L and E during cycling process. Phenol in electrolyte will enter into the film when PAN is controlled as E; while release from the film into electrolyte again when PAN is modulated to L. Phenol enter or release from film can controlled freely by modulating the potential of PAN films, this characteristic can be used to separate the phenol from the solution.

Key words: Conducting polyaniline, electrochemical quartz crystal microbalance, Phenol, Electrochemically controlled separation