Synthesis and Characterization of Aqueous Colloidal Dispersions of Poly(Vinyl Alcohol)/Polyaniline Particles

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Abstract
Colloidal polyaniline has been prepared in acidic aqueous media by a modified chemical polymerization of aniline in the presence of a tailor-made polymeric surfactant. The surfactant which acts as a steric stabilizer used in this study is derivatized poly(vinyl alcohol-co-vinyl acetate). This surfactant contains pendant aniline units which participate in the aniline polymerization, resulting in the formation of sterically-stabilized polyaniline particles which have a non-spherical “rice-grain” morphology. It is shown that this novel form of polyaniline is more processable than the bulk powder that is normally obtained from a conventional chemical synthesis. The solid-state conductivity of solution-cast films or compressed pellets of these dispersions is surprisingly high (≃1 S/cm), despite the presence of the insulating outer layer of chemically-grafted stabilizer. We have characterized these polyaniline colloids by a wide range of techniques including electron microscopy, cyclic voltammetry and Raman, visible absorption and X-ray photoelectron spectroscopy.