Electrosynthesis of poly(o-phenylenediamine) in a room temperature ionic liquid D. Zane a , A. Raffaele a , A. Curulli a , G.B. Appetecchi b , S. Passerini b, * a Istituto per lo Studio dei Materiali Nanostrutturati (ISMN)-CNR, I-00161 Rome, Italy b Ente Per le Nuove Tecnologie, l’Energia e l’Ambiente (ENEA), TER, Centro Ricerche Casaccia, I-00123 Rome, Italy Received 10 April 2007; received in revised form 14 May 2007; accepted 4 June 2007 Available online 9 June 2007 Abstract Poly-o-phenylenediamine (PoPD) thin films were synthesized electrochemically on platinum electrodes in the room temperature ionic liquid (IL) N-butyl-N-methylpyrrolidinium (nonafluorobutanesulfonyl)-(trifluoromethanesulfonyl)imide (PYR 14 IM 14 ). The polymer films were further characterized by electrochemical analysis and the results are compared with those obtained in conventional H 2 SO 4 aqueous solution. The polymer films obtained in the IL-based electrolyte showed a good adherence on Pt and appeared attractive for the realization of biosensors since they showed a good selectivity with respect to the most common interferent compounds. PoPD films deposited from IL-based electrolytes were investigated in solutions containing compounds as ascorbate and acetaminophen, which are common interferents in electrochemical biosensor analysis, and proved satisfying for application in biosensors. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Electrochemistry; Electropolymerization; Ionic liquid; PYR 14 IM 14 ; Conductive polymers; Poly-o-phenylenediamine 1. Introduction Poly-diaminobenzene polymers have shown consider- able interest worldwide due to their possible use in many fields such amperometric biosensors, sensors and detectors, electrochromic devices, anticorrosion coatings for metals, electric and electronic materials. Electrosynthesized poly- mers are materials easily prepared, which conductivity is tuneable by changing the electrochemical deposition method (i.e., galvanostatic, potentiostatic or voltammetric) and/or the chemical conditions in the polymerization bath. For example, PoDP obtained in acidic media is conductive while it is non-conductive otherwise. Obviously, the elec- trosynthesis of a polymer in its non-conductive form results in the deposition of a very thin layer because the growth of the insulating polymer film is self-limited. In this condition, polymeric films of thicknesses not exceeding 100 nm are obtained [1,2]. Such thin polymer films are very useful for sensor applications since the low thickness allows products and substrates to diffuse quickly to the electrode surface while being very effective in blocking interfering species. On such thin films it is possible to immobilize both enzymes and mediators to develop amperometric biosensor that shows good performances in term of sensitivity and fast response. Ionic liquids represent a new class of interesting green solvents for electrochemical applications because of their high ionic conductivity, negligible vapour pressure and wide electrochemical stability window. These properties make them suitable as electrolytes and solvents in one [3,4]. Ionic liquids have been tested in a number of applica- tions regarding polymers and have showed very interesting performance especially in terms of electrochemical stability [5,6]. Recently a number of papers have focused on the use of ILs as electrolytes (or electrolyte components in mixture with other chemicals) for the electrosynthesis of conductive polymers [7–16]. However, only a few works reported in literature dealt with the polymerization of aniline [17] and o-phenylenediamine [18]. 1388-2481/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.elecom.2007.06.002 * Corresponding author. E-mail address: passerini@casaccia.enea.it (S. Passerini). www.elsevier.com/locate/elecom Electrochemistry Communications 9 (2007) 2037–2040