Effect of the prolonged electrode potential cycling on the impedance response of poly(o-aminophenol) (POAP)

R. TUCCERI

Sofía

Conferencia; ECIS 2013, 27th Conference of European colloid and Interface Society; 2013

ECIS 2013, 27th Conference of European colloid and Interface Society

Effect of the prolonged electrode potential cycling on the impedance response of poly(o-aminophenol) (POAP) film electrodes Ricardo Tucceri Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA). CONICET, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Sucursal 4, Casilla de Correo 16, (1900) La Plata, Argentina. corresponding author?s e-mail: rtucce@gmail.com   The aim of this work was to study the effect of prolonged potentiodynamic cycling (-0.2 V < E < 0.5 V vs. SCE) on the conducting properties of poly(o-aminophenol) (POAP) film electrodes. The Electrochemical Impedance Spectroscopy (EIS) was employed in this study to obtain dependences of charge-transport parameters on the degree of deactivation (qcd) of the polymer after prolonged electrode potential cycling. Impedance diagrams of POAP films were analyzed on the basis of two different models 1,2. While diffusion coefficients for electron (De) and ion (Di) transport decrease, interfacial resistances related to ion (Rif|s) and electron (Rm|f, Ref|s) transfer across the different interfaces involved in the metal/polymer film/solution system increase as the degree of deactivation increases. Fig. 1 shows the Rm|f vs. qcd dependence. The slower electron transport with the increase in the degree of deactivation was attributed to the increase of the electron hopping distance between redox sites. Transport parameters, such as, Rif|s and Di, were associated with proton movements. POAP films maintain their conducting properties almost unaltered for about 500 potential cycles at a scan rate of 0.010 V s-1. However, a loss of conductivity was observed as the number of potential cycles was extended beyond 500. Fig. 1. Metal-polymer interfacial electron-transfer resistance (Rm/f) as a function of qcd. Electrolyte: 0.1 M HClO4 + 0.4 M NaClO4 + 2 x 10-3 M (HQ/Q) solution.   Literature: 1.      Vorotyntsev,  M.A., Deslouis, C., Musiani, M.M., Tribollet, B., Aoki, K., 1999, Transport across an electroactive polymer film in contact with media allowing both ionic and electronic interfacial exchange, Electrochim. Acta, Vol. 44, pp. 2105-2115. 2.      Rodríguez Nieto, F.J., Tucceri, R.I., 1996, The pH effect on the Charge         Transport at Redox Polymer-Modified Electrodes. An ac Impedance Study applied to Poly (o-aminophenol) Film Electrodes, J. Electroanal. Chem. Vol. 416, pp. 1-24.