Polyaniline was synthesized in the presence of tanninsulfonic acid to yield a product tanninsulfonic acid-doped polyaniline (TANI-PANI) that is water-dispersible. Several samples ranging from 0 to 70% tanninsulfonate (TS) were prepared. These samples were then evaluated for differences in dispersibility, particle size, and conductivity. As the percent of TS in the samples was increased, the water-dispersibility of the TANI-PANI also increased. The particle size of the samples as well as the conductivity of the samples decreased with increasing percentages of TS in the samples. After extensive washings, however, the conductivity remained fairly constant (similar to 0.5 S/cm) regardless of the amount of TS in the samples. Additionally, elemental analysis, TGA, and IR data were used to demonstrate that the TS may be grafted to polyaniline during the synthesis of TANI-PANI. (c) 2006 Wiley Periodicals, Inc. I Appl Polym Sci 103: 2113-2119,2007