Polymerization of aniline in ice

It was observed that the oxidative polymerization of aniline proceeded well not only in the liquid mixtures at 20 degrees C or -5 degrees C but also in ice at -24 C. The oxidative polymerization took place in the solutions of strong acid (0.1 M sulfuric acid) or weak acid (0.4 M acetic acid). It is proposed that the initially generated polyaniline participates in the further redox process, leading to new polyaniline formation. The molecules of the monomer (aniline) and oxidant (peroxydisulfate) thus react by transferring electrons through the conducting polyaniline, without the need to be in direct contact. The polymerization in the liquid phase or in the solid frozen state changes the morphology of the polyaniline. Polyaniline nanogranules or nanotubes are produced in the liquid state, while thin nanowires of 20 nm diameter connecting the submicrometre polyaniline particles have been observed when the polymerization took place in ice. (C) 2008 Elsevier B.V. All rights reserved.