Polyaniline (PANI) nanotubes (similar to 180 nm in diameter) were synthesized in the presence of sodium dodecylbenzenesulfonate (SDBS) as a micellar template and dopant, whereas PANI/NiO nanobelts (300-700 nm in diameter) were obtained with the addition of NiO nanoparticles (similar to 10 nm in diameter). Results showed that the size of PANI/NiO composite nanobelts increased with an increase content of NiO nanoparticles. XRD, Fourier transform infrared (FTIR) and UV-vis spectroscopy were used to characterize the chemical structures of PANI nanotubes and PANI/NiO nanobelts. The thermal stability and conductivity of samples were affected by the content of NiO. The coordination bonds between NiO and aniline were the key factor that resulted in the morphological change of PANI. (c) 2007 Elsevier B.V. All rights reserved.