Electrochemistry of Conductive Polymers 47: Effects of Solubilizers on 3,4-Ethylenedixoythiophene Oxidation in Aqueous Media and Properties of Resulting Films

Effects of a few solubilizers on electrochemical oxidation of 3,4-ethylenedioxythiophene (EDOT) in aqueous media and on electrochemical, morphological, and electronic properties of its resultant thin polymer (PEDOT) films have been investigated by Fourier transform electrochemical impedance spectroscopic and current sensing atomic force microscopic experiments. Two different types of solubilizers including hydroxypropyl-β-cyclodextrin (HpβCD) forming an inclusion complex with a hydrophobic species and two anionic surfactants forming micelles, sodium dodecylsulfate (SDS) and sodium dodecylsulfonate (SDBS), were used due to the low solubility of the EDOT monomer in aqueous media. Results indicate that anionic surfactant micelles protect electrogenerated cationic species of monomers and oligomers by encapsulating them, leading to formation of polymer films of better properties. The polymer growth characteristics were shown to be closely related to electrical properties of resultant polymer films; PEDOT films obtained in the presence of SDS showed the best growth, ion transport, electrochemical, and electronic properties.