On the pH dependence of electroactivity of poly(methylene blue) films

V. PFAFFEN; P. I. ORTIZ; S. I. CÓRDOBA DE TORRESI; R. M. TORRESI

ELECTROCHIMICA ACTA

Elsevier

Lugar: Holanda; Año: 2010 vol. 55 p. 1766 - 1771

0013-4686

The electrochemical behavior of Poly(methylene blue) on different electrodes has been investigated by electrochemical quartz crystal microbalance and in situ spectrophotometric measurements coupled to cyclic voltammetry. Polymeric films were obtained potentiodinamically and the charge transport mechanism analyzed. The electrochemical results show that polymer electroactivity depends not only on pH but also on the substrate. Charge compensation changes with both pH and the size of the anions showing a transition in the pH range of polymer pKa. It was demonstrated by spectroelectrochemical experiments that the electroactivity of the film depends on the radical/radical cation equilibrium. The potentials where the most electroactive species are formed have been determined.