Polyaniline (PANI)/titanium dioxide (TiO2) composites were prepared with a chemical oxidation polymerization of aniline monomer (ANI) with various molar ratios between ANI and para toluenesulfonic acid (p-TSA). To find an effect of the [ANI]:[p-TSA] molar ratio on the electrochemical properties of the prepared PANI/TiO2 composites, the composites were synthesized under same conditions except the p-TSA concentrations. The prepared composite films had more homogeneous TiO2 dispersion with changing [ANI]:[p-TSA] molar ratios from 6:1 to 1:1. p-TSA surfactant-like doping acid helped the dispersion of TiO2 particles in the PANI matrix. PANI covering the TiO2 surfaces was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Prepared PANI films on the TiO2 particles had the smoothest surface when the ANI and p-TSA had 1:1 molar ratio in the reaction solution. The composite prepared with molar ratio [ANI]:(p-TSA] of 3:1 had the highest capacitance (800 F g(-1)) among the prepared composites. (C) 2012 Elsevier Ltd. All rights reserved.