Electropolymerization of 2-methoxyaniline. Polymerization kinetics and phenazine insertion at low monomer concentration

Abstract

The electropolymerization of 2-methoxyaniline (MOA) has been found to yield products having structure and properties dependent on the monomer concentration, with the insertion of phenazinic units giving a redox-type polymer at low concentrations. The kinetics of this process is studied in 1 M HClO₄ solutions containing different monomer concentrations. The voltammetric results are compared with the electropolymerization, in similar experimental conditions, of other aryl amines such as aniline and 2-methylaniline. The effect of dimeric additives on the polymerization rate of MOA is also studied. A change in the kinetic behavior is found at MOA concentrations of about 30–60 mM. An electropolymerization mechanism for 2-methoxyaniline is proposed through a reaction scheme similar to that of aniline, with the inclusion of a step consisting in a head-to-head coupling of oligomers and/or polymer chains yielding phenazine-type units, that effectively works as a termination step. The resistivity increase, in the conductive state, due to the insertion of redox units is also considered. The experimental results are interpreted on the basis of this mechanism.