Electrochemical synthesis of functional polypyrrole nanotubes via a self-assembly process

We successfully electrochemically polymerized functional polypyrrole (PPy) nanotubes via a self-assembly process in the presence of methyl orange (MO). The influence of polymerization conditions, such as working electrodes and electrochemical polymerization time, on the tubular morphology was discussed. A fibrillar precipitate of MO formed via electric flocculation on the electrode in a neutral aqueous solution prior to the polymerization of pyrrole and acted as a template for the subsequent growth of PPy nanotube. The importance of the MO aggregation in the forming process of PPy nanotubes was revealed by the observation that no tubular structure of PPy formed in dilute MO aqueous solution. The PPy–MO nanotubes obtained showed a high conductivity and an ability to alter photochemically the electrical behavior. In addition, as-prepared PPy tubes could be converted to the corresponding carbonized tubes when they were subjected to thermal treatment under an inert atmosphere.