THE EFFECT OF PH ON THE CHARGE TRANSPORT AT REDOX POLYMER-MODIFIED ELECTRODES - AN AC IMPEDANCE STUDY APPLIED TO POLY(O-AMINOPHENOL) FILM ELECTRODES

摘要

Impedance spectroscopy was used to study the effect of solution pH on the electrochemical behavior of poly(o-aminophenol) (POAP) modified electrodes. An a.c. impedance expression was derived on the basis of a model which considers a chemical reaction influencing the dynamics of the charge transport process by electron hopping between redox sites. Experimental impedance spectra of POAP films at different pH values of the bathing electrolyte were fitted by means of this theoretical equation. A pK(a) value for the proposed protonation reaction could be estimated from the model. [References: 62]