The ageing response of Polyaniline: interpretation of the voltammetric data by an Extended Feldberg’s Model

W. MARMISOLLÉ; M. I. FLORIT; D. POSADAS

Niza, Francia

Congreso; 61st Annual Meeting of the International Society of Electrochemistry (ISE); 2010

International Society of Electrochemistry (ISE)

Very often the ageing response of conducting polymers (CP) has been followed by measuring the time response of the voltammetric peak parameters jp and Ep during the first voltammetric scan in the positive direction, after the ageing time. That response gives a rate law in which the extension of the reaction changes logarithmically with the ageing time. In this way the electrochemical response would reflect only the conformational changes that happen during ageing. However, it is well known that the electrochemical response of CP contains an indeterminate amount of capacitive contribution. We have previously shown that electrochemical response of CPs can adequately be represented by the Extended Feldberg model. In this way it is possible to analyze the electrochemical response after ageing.In this work we studied the ageing of Pani in acidic media. Particular attention is paid to the influence of the thickness and the ageing potential on the ageing process.The temporal variation of the voltammetric response is quantitatively analyzed and the parameters of the model are fitted. The change in the voltammetric parameters allows us to conclude that, as the polymer film ages variations in the interaction energies between the redox centres occur.