Síntese e caracterização de nanocompósitos formados de polipirrol dopado com índigo carmim e nanopartículas de ouro.

Abstract

The present work describes the synthesis and characterization of nanocomposites of indigo carmine doped polypyrrole embedded with gold nanoparticles, aiming to study the effect of the metallic nanoparticles on the electrochromic properties of polypyrrole doped with indigo carmine. The first part of this work concerned the determination of the ideal synthesis condition, (indigo carmine concentration, synthesis temperature, electrolyte composition and electrochemical method for film deposition), to obtain nanocomposites of indigo carmine doped polypyrrole embedded with pre-synthesized (PPY/IC/NPAu) and in situ synthesized gold nanoparticles, by using HAuCl4 in the polymerization electrolyte solution (PPY/IC/HAuCl4). The ideal synthesis parameters were obtained by considering the films with lowest energy gap, obtained from optical measurements. The second part concerned the optical, structural, morphological, electrochemical and electrochromic characterization of the obtained films, by using UV-Vis spectroscopy, infrared-spectroscopy, scanning electron microscopy, cyclic voltammetry and in situ UV-Vis spectroelectrochemistry. The obtained results shows efficient doping by indigo carmine, presenting optical spectra characteristic of polaron state and uniform morphology. In addition, the results clearly show improved charge density and enhanced electrochromic properties from the nanocomposite PPY/IC/HAuCl4 synthesized at 10ºC, presenting optical contrast 2.2 times higher than PPY/IC obtained at the same conditions.