The castor oil sulfate (COS), produced by the sulfonation of the castor oil (one of the most promising
renewable sources), was used as both the surfactant and the dopant in the chemical oxidative poly-
merization of pyrrole. The resulting castor oil sulfate doped polypyrrole nanospheres (PPy/COS) were
characterized with FTIR, UV–vis, TGA, zeta potentials and TEM techniques. It was found that their diam-
eter decreased and their dispersing stabilities in water increased with the increasing of feeding ratio of
COS. The PPy/COS nanospheres possess high electrical conductivity at room temperature and the weak
temperature dependence of the conductivity.