Pyrrole Nanoscaled Electropolymerization into Zeolite Channels

Incorporation of polymer network into inorganic hosts is of great interest since this enables us to combine characteristics of the parent constituents as a consequence of their molecular level interaction. Zeolites are one of the most promising host materials owing to their highly ordered pore systems, and the surface is negatively charge-balanced with exchangeable cations[1]. The great diversity of structural frameworks could assist to the synthesis of polymer chains limited to single chains or molecular wires. The first synthesis of Polypyrrole (Ppy) in intracrystalline channels of Y-zeolite (0.8 nm windows) has been achieved by Bein and Enzel[2]. On the other hand, Phani et al.[3] succeeded in the electrochemical polymerization of aniline in Y-zeolite. As a general rule, the conductivity values of the resulting host-polymer composite are always lower than those of the conventionally synthesized bulk polymers. The low conductivity could be ascribed to the defects in the polymer chains as a consequence of the host topochemistry or to the electrical carriers trapping by the framework of the inorganic solids [4]. Electrochemical synthesis of Ppy sorbed in zeolite structures is less investigated. Coelectrodeposition of type A zeolite and Ppy was achieved by Rollison and coworkers, obtaining a uniform particle-polymer coatings [5]. The aim of the present work is the electrochemical synthesis of Ppy nanowires in the channels of clinoptilolite. Also ppy nanowires were electrosynthesized into Y-zeolite channels and the electrochemical behavior of two nanocomposites were compared