Polyaniline-gold nanocomposite system

Nanostructured composite materials of polyaniline (PANI) with gold clusters of different sizes and amounts have been produced. PANI films of the same thickness were grown electrochemically on platinum substrates. Then nucleation of gold clusters in the PANI film was initiated by chemical reduction of tetrabromoaurate ion in acidic solution. The spontaneous process of gold cluster formation was evaluated using UV-vis spectroscopy, scanning electron microscopy, and the Kelvin probe. It was found that the amount and size distribution of gold clusters vary with immersion time. The measured work function of the PANI/Au composite changes its magnitude according to the changes in composition of the materials. Despite the fact that the preparation method makes the gold cluster growth difficult to control in size and in distribution, it is of interest to applications for solid-state potentiometric sensors, batteries, supercapacitors, or catalysis since it modifies the electron affinity of the synthesized conducting polymer/gold composite. (C) 2003 The Electrochemical Society.