Polyaniline stabilized highly dispersed gold nanoparticle: An in-situ chemical synthesis route

The in-situ chemical synthesis of polyaniline stabilized highly dispersed gold nanoparticle, was studied. HAuCl₄ stock solution was added to a solution of aniline dissolved in methanol. The solution became turbid and viscous and the sample was collected for TEM and UV-vis spectroscopic analysis. The solution was dried under vacuum and the resulting solid mass was characterized using IR and Raman spectroscopy. The mechanism suggested was that H⁺ ion from HAuCl₄ leads to the formation of PhNH ₃⁺ type species. [AuCl₄]^- acts as the oxidizing agent and is capable of oxidizing PhNH₃⁺. The resultant oxidative product is polyaniline and during polymerization each step involved the release of electrons that reduce the gold ion to form gold atoms. It was found that the morphology of the metal-polymer composite could be influenced by the synthesis conditions employed.