The azanes: A class of material incorporating nano/micro self-assembled hollow spheres obtained by aqueous oxidative polymerization of aniline

The nature of the product of the conventional aqueous oxidative polymerization of aniline by ammonium peroxydisulfate and HCI is extremely sensitive to the pH of the polymerization system. This is observed when the concentrations of reagents are sufficiently dilute (at a pH of 3-4) to isolate the first-formed product of the reaction which we believe is a member of the class of azanes, polymeric or oligomeric species containing a N-N backbone in which each N atom is forming three covalent single bonds. The brown solid isolated has been characterized by its elemental analysis, UV-vis, FTIR, and H-1 NMR spectra. We believe, in the simplest case, it may be an organic-substituted hexa-azane. It is completely different in every way from any known form of polyaniline, in any oxidation state, of any degree of protonation. It is isolated as hollow microspheres (diameter, similar to 1.5-6 mu m), which have an essentially identical SEM appearance to hollow microspheres previously ascribed to conventional polyaniline. As the pH of the reactant system falls during the polymerization, polyaniline in its conventional forms begins to be formed; however, especially if the pH is held constant by a buffer solution, the pure azane can be isolated. We believe the azanes open up a new field of self-assembled nano/micro particles of very considerable potential applicability to the emerging field of nanoscience. (c) 2006 Elsevier B.V. All rights reserved.