Formation of nanostructured polyaniline by dopant-free oxidation of aniline in a water/isopropanol mixture

Abstract

Nanostructured polyaniline (PANI) was synthesised by the oxidation of aniline in a water/ isopropanol (propan-2-ol, IPA) (50 vol. %) mixture, without added acid, using ammonium peroxydisulfate (APS) as an oxidant. Influence of the IPA co-solvent and the reaction time on the molecular structure, morphology and properties of synthesised PANI samples was studied by FTIR, Raman, and UV-VIS spectroscopies, scanning and transmission electron microscopies (SEM and TEM), and conductivity measurements. The course of the reaction was followed by monitoring changes in the temperature and acidity of the reaction medium. The results were compared with those obtained for PANI prepared in water without IPA under the same reaction conditions. The importance of the solvation effects, dielectric constant of the solvent, and the enthalpy of mixing of IPA with water on the course of the polymerisation reaction and on the properties of polymeric products in the water/IPA medium in comparison with those in water was pointed out. © 2013 Institute of Chemistry, Slovak Academy of Sciences.