Solid phase photopolymerization of pyrrole in poly(vinylchloride) matrix A.W. Rinaldi, M.H. Kunita, M.J.L. Santos, E. Radovanovic, A.F. Rubira, E.M. Girotto * Grupo de Materiais Polime ´ricos e Compo ´sitos (GMPC), Departamento de Quı ´mica, Universidade Estadual de Maringa ´, Av. Colombo 5790, 87020-900 Maringa ´ PR, Brazil Received 20 January 2005; received in revised form 12 April 2005; accepted 16 May 2005 Available online 14 July 2005 Abstract Electrically conductive films were obtained by solid phase photopolymerization of pyrrole (Py) into a poly(vinylchlo- ride) (PVC) matrix. We attempted to characterize the structure, electrochemical and thermal properties, and morphol- ogy of the resulting polypyrrole/PVC blend. The blend obtained has low conductivity and rather poor electroactivity due to the loss of conjugation length of polypyrrole (PPy) provoked by halogenation. Micrographs of cryofracture sur- face suggested two distinct phases, and thermogravimetric analysis revealed a low thermal stability of the blend. On the basis of our experimental results, we propose a reaction mechanism that explains the PPy formation in solid phase induced by UV light. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Polypyrrole; Photopolymerization; Poly(vinylchloride); Conductive blends 1. Introduction Since their discovery, intrinsically conductive poly- mers (ICP) have attracted the attention of the industry and the scientific community due to their optical and electrical properties and been applied in a number of areas. Besides the electrochromism and the photoelectro- chemistry of ICP, which are a consequence of their elec- trical properties, their conductivity can be engineered for appropriate electronic devices [1]. However, the applica- tion of ICP in the plastic and electro-electronic industries is limited by its poor mechanical properties. On attempt- ing to overcome this feature, research groups have de- voted their efforts to develop conducting and flexible films. Blends containing ICP and thermoplastics, poly- amides, polyesters, or elastomers, are used in the produc- tion of materials for electrochromics [2–4], batteries [1–6], sensors [7–10], attenuators, capacitors, photo- diodes [11–14], photoelectrochemical cells [15–17], and antistatic coatings [1,18,19]. It is well established that the electrical, optical, and magnetic properties of ICP are strongly dependent on synthesis conditions, which can be chemical, electrochemical, or photochemical [20,21]. In the last decade, the use of light had an impor- tant role in the development of the microelectronic indus- try and computer science, (from the point of view of the ultra fast information transmission) and as a source of energy. In addition, light can also be used to induce 0014-3057/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.eurpolymj.2005.05.029 * Corresponding author. Tel.: +55 44 2614332; fax: +55 44 2635784. E-mail address: emgirotto@uem.br (E.M. Girotto). European Polymer Journal 41 (2005) 2711–2717 www.elsevier.com/locate/europolj EUROPEAN POLYMER JOURNAL