Redox transformations of polyaniline nanotubes: Cyclic voltammetry, infrared and optical absorption studies

Polyaniline (PANI) nanotubes have been obtained by the standard template synthesis method [C.R. Martin, Science 266 (1994) 1961]. A new method of the separation of PANI nanotubes from the template is described, enabling easy deposition of nanotubes on the conductive support. The nanotubes were investigated by cyclic voltammetry, infrared reflection–absorption spectroscopy and optical absorption spectroscopy. Cyclic voltammograms of PANI nanotubes reveal differences in comparison to conventional PANI films. In particular, an additional reduction peak is observed in initial cycles. Spectroscopic results support the assignment of the additional peak in the cyclic voltammogram to the reduction of bipolaronic species trapped within nanotubes structure.