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Electrochemical switching of conducting polymers: A variable resistance transmission line model

Publication Type:

Journal Article


J. Electroanal. Chem. (Switzerland), Volume 590, Number 1, p.76 - 81 (2006)



capacitors;conducting polymers;electrical conductivity;electrochemistry;finite difference methods;oxidation;reduction (chemical);transmission line theory;transmission lines;voltammetry (chemical analysis);


We present a model to explain some anomalous properties that have been observed in the electrochemical switching of conducting polymers, including: moving phase fronts on charging from the reduced, insulating state; residual charge in the polymer after complete reduction; and, the sharp anodic peak and flattened cathodic peak observed in cyclic voltammograms. The electrochemistry is modeled as an RC transmission line, typical of a distributed capacitor network, with the addition that the oxidation state dependence of the polymer's electronic conductivity is explicitly included. The transient charges and currents during potentiostatic steps and linear sweeps are solved using the method of finite differences in the time domain, and results compare well with experiment in experimental geometries where electron transport is rate limiting. The model can also be generalized to other geometries provided that variation in the other physical parameters with oxidation state can be determined. [All rights reserved Elsevier]


electrochemical switching;conducting polymers;variable resistance transmission line model;moving phase fronts;charging;reduced state;insulating state;residual charge;reduction;anodic peak;cathodic peak;cyclic voltammogram;RC transmission line;distributed capacitor network;oxidation state;electronic conductivity;transient charge;transient current;potentiostatic step;linear sweep;time domain finite difference method;rate limiting electron transport;