In the present study, a conductive polyaniline-dodecyl benzene sulfonic acid (PANI-DBSA) complex, prepared by a thermal doping process, and its blends with thermoplastic polymers, prepared by melt processing, were investigated. PANI- DBSA characterization included conductivity measurements, morphology, crystallogra- phy, and thermal behavior. The blends' investigation focused on the morphology and the interaction between the components and on the resulting electrical conductivity. The level of interaction between the PANI and the matrix polymer determines the blend morphology and, thus, its electrical conductivity. Similar solubility parameters of the two polymeric components are necessary for a high level of PANI dispersion within the matrix polymer and, thus, enable the formation of conducting paths at low PANI content. The morphology of these blends is described by a two-structure hier- archy: (a) a primary structure, composed of small dispersed polyaniline particles, and (b) a short-range fine fibrillar structure, interconnecting the dispersed particles. q 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 243-253, 1997