Synthesis and characterization of polyaniline prepared in the presence of nonionic surfactants in an aqueous dispersion

Polyaniline (PANI) has been prepared in water-dispersed medium in the presence of nonionic surfactants. Large range of surfactants was selected based on their chemical composition and their hydrophile-lipophile balance (HLB). Three types of nonionic surfactants were chosen: three nonylphenolethoxylates, a surfactant bearing an amide group, and surfactants containing an amine function. The experimental conditions were optimized and a dispersion process was developed for the direct synthesis of a doped PANI. The polymerizations were monitored by pH measurements and UV spectroscopy and the kinetic behavior was determined. The conductive PANI was systematically characterized and the effect of the surfactant established. The PANI/surfactant affinity was estimated. The doping level and the surface composition of the PANI particles have been studied by X-ray photoelectron spectroscopy (XPS). Absorption spectra of PANI in a large range of pH showed the transition from emeraldine salt to emeraldine base form. All the results were compared to the properties of a conventional HC1 doped PANI and a dodecylbenzenesulfonic acid (DBSA) doped PANI. (c) 2005 Elsevier B.V. All rights reserved.