Highly carbonized polyaniline micro- and nanotubes

Abstract We have obtained unique highly carbonized polyaniline micro- and nanotubes as a new, thermally stable nanomaterial for nanosensors and nanodevices with a wide range of possible applications, comparable to carbon nanotubes. Polyaniline nanostructures are easy to prepare and handle in wet conditions, including controlled growth. Temperature-induced transformations of polyaniline micro- and nanotubes into highly carbonized analogues have been observed at and above 800 °C, while the temperature was elevated slowly from 20 °C up to 1100 °C. Carbonized products have the same morphology (micro- and nanotubes), but a lower spin density than the starting material (e.g. 10 14  g −1 for the sample heated at and above 800 °C, and 10 19  g −1 before heating). Simultaneously, the electrical conductivity changes from 7.4 × 10 −5  S/cm for the starting material to 4.8 × 10 −9  S/cm, 1.3 × 10 −11  S/cm and finally 2.4 × 10 −6  S/cm for samples obtained at room temperature, 250 °C, 500 °C and 800 °C, respectively. Chemical transformations and unique molecular structures formed are discussed. Applications in nanotechnology, including sensors and electronic nanodevices, are expected in the light of experiments already performed.