Polyaniline prepared in ethylene glycol or glycerol

Oxidations of aniline or aniline hydrochloride have been carried out in ethylene glycol or glycerol and in their mixtures with water. Ammonium peroxydisulfate was used as oxidant. The oxidation of aniline is exothermic and changes in temperature were monitored to follow its progress. The effect of the solvents on the course of oxidation, morphology, and properties of final products has been studied by scanning electron microscopy, FTIR spectroscopy, and conductivity measurements. It is proposed that the reduction of dielectric constant of the reaction medium results in the reduced dissociation of ionic species that take a part in oxidative polymerization. Consequently, the addition of an organic solvent has a similar effect as a decrease in the acidity of the reaction mixture. Conductivity and morphology depend on the mole ratio of oxidant and monomer, and the type and volume fractions of organic solvents, viz, ethylene glycol and glycerol, which were used in reactions. (C) 2011 Elsevier Ltd. All rights reserved.