Polyaniline-polypyrrole (PANT-PPy) composite was prepared by in situ polymerization of pyrrole in PANT dispersion using FeCl3 center dot 6H(2)O as oxidant and sodium dodecyl benzene sulfonate (SDBS) as surfactant. Different synthesis conditions of PANT dispersion including the relative concentration of aniline and SDBS and the amount of acid (HCl) on the morphology and conductivity of the resulting composites were investigated. Fourier transformation infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) patterns, and contact angles of the composites showed there existed certain interaction between PANT (or PANI-SDBS) and PPy. (c) 2007 Wiley Periodicals, Inc.