Highly ordered polyaniline (PANI) array was prepared by self-assembly method and using inorganic acids as dopants. The PANI array was characterized by scanning electron microscopy, Fourier transform infrared spectra, and X-ray diffraction, and the influence of preparation conditions on the morphology and structure of the PANI arrays is discussed. It is found that the morphology and structure of the PANI arrays strongly depend on the kinds of dopant. The resulted PANI has a emeraldine molecular structure and highly oriented arrangement. (c) 2008 Elsevier Ltd. All rights reserved.