Spontaneously formed polypyrrole microtubes: incandescence and graphitization

Emission of strong visible light from the polypyrrole microtube, spontaneously formed during electrochemical polymerization of pyrrole, was observed by applying voltage between the two ends of a single microtube. The molecular structure of the microtube gradually changes into that of graphite during the light emission or the incandescence, which is shown by the data of elemental analysis and Raman spectra as well as temperature dependence of electrical resistance at low temperature.