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

F VIVA; E. M. ANDRADE; MI FLORIT,; F. V. MOLINA

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Royal Society of Chemistry

Lugar: Londres; Año: 2002 vol. 4 p. 2293 - 2300

1463-9076

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 1M 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.