Metal ion-driven synthesis of polyaniline composite doped with metallic nanocrystals at the boundary of two immiscible liquids

In this work, silver and gold–polyaniline composite materials were chemically synthesized at the nitrobenzene/water interface. Aniline (monomer) was dissolved in nitrobenzene and the oxidizing agent (either silver (I) or gold (III)) was dissolved in water. Metals, which were formed during the reaction were in nano- and microcrystalline forms and were partially embedded in the polymer. The forms of gold and silver crystallites found in the synthesized composites differed significantly. The rate of growth of the PANI-Ag and -Au composites and their morphologies depended on concentration of the reagents in both phases. The average size of the gold crystals was smaller compared to silver and was in the range of 20–25 nm. The obtained composite materials were characterized by cyclic voltammetry, scanning electron microscopy, and Raman spectroscopy. The pernigraniline species of polyaniline dominated in the entire volume of the PANI-Au composite and in parts of the PANI-Ag material located at the aqueous solution side, while partially oxidized emeraldine was the main component of PANI-Ag at the organic phase side.