Synthetic Metals 161 (2011) 1313–1318 Contents lists available at ScienceDirect Synthetic Metals journa l h o me page: www.elsevier.com/locate/synmet Electrochemical synthesis and corrosion behavior of polyaniline-benzoate coating on copper Milica M. Gvozdenovi ´ c a,∗ , Branimir Z. Jugovi ´ c b , Jasmina S. Stevanovi ´ c c , Branimir Grgur a , Tomislav Lj. Triˇ sovi ´ c b , Zvonimir S. Jugovi ´ c d a Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia b Insitute of Technical Science, Serbian Academy of Science and Arts, Knez Mihajlova 35, 11000 Belgrade, Serbia c Institute of Chemistry Technology and Metallurgy, Njegoˇ seva 12, 11000 Belgrade, Serbia d Technical Faculty ˇ Caˇ cak, University of Kragujevac, Svetog Save 65, 32000 ˇ Caˇ cak, Serbia a r t i c l e i n f o Article history: Received 4 January 2011 Received in revised form 3 March 2011 Accepted 26 April 2011 Available online 25 May 2011 Keywords: Electrochemical polymerization Sodium benzoate Polyaniline Copper a b s t r a c t Electrochemical polymerization of polyaniline (PANI) coating on copper electrode was performed gal- vanostatically in the current density range between 0.50 and 1.25 mA cm -2 , from aqueous solution of 0.3 mol dm -3 sodium benzoate and 0.2 mol dm -3 aniline. The corrosion behavior of PANI coated copper and copper electrode exposed to 0.5 mol dm -3 sodium chloride solution was investigated by potentiody- namic and electrochemical impedance spectroscopy techniques. It was observed that thin PANI (5 m) coating had provided efficient protection (∼96%) to copper in 0.5 mol dm -3 sodium chloride solution. Unusual initial impedance behavior to that normally observed with conventional organic coatings was attributed to dedoping of benzoate anions from the polymer coating. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The unique properties of electroconducting polymers (ECP), such as: electrochemical activity, environmental stability, eases of synthesis procedures both chemical and electrochemical [1–9], permits them to be considered in wide range of various practical applications: electronic devices, rechargeable power sources, sen- sors, biosensors, magnetic shielding and active corrosion protection as well [10–18]. Copper and large numbers of its alloys are widely used in industrial application such as process equipments, electrical and electronics devices, marine etc. Apart from high electrical and ther- mal conductivity and excellent formability, copper also exhibits good corrosion resistance; however it corrodes in variety of aggres- sive environments [18]. The corrosion protection strategy of copper is usually based on inhibition, using organic compounds mainly benzotriazoles, aminotriazole and its derivates [19–24]. Apart from good protective properties of inhibitors in variety of corrosive environments, they are quite toxic, hence application of elec- troconducting polymers (ECP) could be considered as possible environmental friendly procedure in corrosion protection of cop- per. Both chemical and electrochemical oxidative polymerization ∗ Corresponding author. Tel.: +381 11 3303695; fax: +381 11 3303695. E-mail address: popovic@tmf.bg.ac.rs (M.M. Gvozdenovi ´ c). are used to obtain ECP. Electrochemical synthesis is favorable per- mitting direct polymer film synthesis on metal surface without oxidizing agent, followed by doping by organic or inorganic ions in a single step. The basic problem related to electrochemical polymer- ization of ECP on copper, in general, is the fact that two competitive processes occur on anode: electrochemical synthesis and deposi- tion of ECP and dissolution of copper on potentials necessary to oxidize the monomer. Hence, it would be beneficial to work with electrolyte which can passivate copper and, on the other hand, permits electrochemical polymerization. Most of the studies devoted to corrosion protection of copper by ECP are connected to use of polypirrole (Ppy). Recently, Bazzaoui et al. have used electrochemical synthesis of PPy on copper and brass from aqueous solution of sodium saccharinate and pyrrole solution, the obtained coating exhibited significant corrosion protection in both chloride and hydrochloride solutions [17]. Redondo and Bres- lin obtained homogenous PPy film electrodeposited on copper from pyrrole containing phosphate solution; the growth of the film was achieved on previously oxidized copper electrode in the phosphate solution. The coating effectively protected copper in a chloride solution [25,26]. Fenelon and Breslin also electrodeposited Ppy coating on Cu, CuZn and CuNi with good protective properties from sodium oxalate solution [27,28]. Herrasti et al. investigated electrochemical synthesis of PPy on previously passivated copper electrodes using different electrochemical techniques, they pointed out that chronopotentiometry seemed to produce best protective 0379-6779/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2011.04.029