Chemical polymerization of 3,4-ethylenedioxythiophene using an aqueous medium containing an anionic surfactant

We found that a good yield of poly(3,4-ethylenedioxythiophene) (PEDOT) was obtained by emulsion polymerization in which an anionic surfactant and Fe2(SO4)3 were used as an emulsifier and an oxidant, respectively. The major feature of this polymerization is that highly conductive PEDOT is formed in an aqueous medium containing such a low concentration of 3,4-ethylenedioxythiophene (EDOT) and Fe2(SO4)3 as 0.05 M. This is most likely due to the polymerization progressing in the innumerable micelles where hydrophobic EDOT is concentrated. The thermal stability of PEDOT obtained here is superior to that of polypyrrole prepared in a similar manner, although its moisture stability is inferior.