Preparation of nanosized metallic particles in polyaniline

The preparation of nanosized gold and palladium particles in polyaniline ha s been carried out via the reduction of AuCl3 or Pd(NO3)(2) by polyaniline in either aqueous media or N-methylpyrrolidinone (NMP), When the reduction of AuCl3 was carried out in NMP solutions of polyaniline, the Au particles were on the order of 20 nm, The reduction of AuCl3 or Pd(NO3)(2) by polyani line in the powder form in aqueous media resulted in the accumulation of th e elemental Au or Pd on the surface of the polyaniline particles. Subsequen t dissolution of the polyaniline in NMP resulted in metal particles of abou t 50 to 200 nm being dispersed in the NMP solution of polyaniline. The rate of metal salt reduction and the size of the metal particles were found to be strongly dependent on the medium used, the initial ratio of metal ions t o polyaniline, and the reaction time. The polyaniline-metal particle system s were characterized using X-ray photoelectron spectroscopy, UV-visible abs orption spectroscopy, and FTIR spectroscopy, Scanning and transmission elec tron microscopy and laser light scattering were used to determine the size of the metal particles in polyaniline. (C) 2001 Academic Press.