"In situ" polymerization was carried out in the presence of titanium dioxide (TiO2) to synthesize TiO2/polyaniline (TiO2/PANI) composite in an aqueous medium containing anionic (sodium dodecylbenzenesulfonate), DBSNa, cationic (tetradecyltrimethylammonium bromide), TTAB, and nonionic surfactants (poly(ethylene oxide) (20) sorbitan monolaurate), Tween 20). The composites were characterized by FTIR, UV-vis spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Gouy balance measurements. The FTIR and UV-vis spectra reveal that the interaction between TiO2/PANI composite and surfactants. The anionic and cationic surfactants incorporated with TiO2/PANI composite structure. The stability of the composites in terms of direct-current electrical conductivity retention was studied in isothermal conditions. Electrical conductivity measurements indicate that the conductivity of TiO2/PANI synthesized in the presence of the cationic surfactant has the highest conductivity value. All composites showed negative mass magnetic susceptibility values. (c) 2007 Elsevier B.V. All rights reserved.