METALLIC AND NONMETALLIC REDOX RESPONSE OF CONDUCTING POLYMERS

The potentiometric response of electrodes coated with polypyrrole or p oly(N-methylpyrrole) films with different doping anions was studied in solutions containing the redox couples: Fe(CN)(6)(3-/4-), Ru(NH3)(6)( 3+/2+) and Fe(III)/Fe(II). The stable potential measures with the elec trodes was the potential of the redox couple. The response time was in stant for polypyrrole doped with dodecylsulphate ions, PPy(DS) and slo w for the polymers doped with mobile anions. On the basis of electroch emical measurements and chemical analysis by EDAX spectroscopy it was found that with the PPy(DS) electrode the potentiometric response was of the 'metallic' type, with no change in the oxidation state of the b ulk polymer. With the other polymer systems studied reduction or oxida tion of the polymer bulk took place when it was in contact with a redo x couple in the solution. (C) 1997 Elsevier Science S.A.