Preparation and characterization of hybrid electrocromic films of nickel hydroxide/polypyrrol

Abstract

Some materials have the capacity to alternate their coloration in response to a change in its oxidation state. This characteristic is called electrochromism and is used in several products, like rearview mirrors and smart windows. The nickel hydroxide has electrochromic characteristics. It can be oxidated, turning into dark brown coloration, that is reverted when it is reduced, returning to be incolor. This hidroxide has two principal structural forms and arrangement, ± and ², being the ± the structure with better electrochemistry properties. This compound can be organized in a thin film deposited on a conducting surface using nanoparticles of this nickel hidroxide and conducting them to the surface by means of the application of an electric field between two electrodes immersed in the nanoparticles' solution because of negative charge's density in its structure. This process is known as electrophoretic deposition. The present project aims to the synthesis of these nanoparticles and their optimization and characterization, including the effect of the addition of polypyrrol (a conducting polymer) in the film composition. With this, it is expected an increment of the electrochemical properties of the obtained material. (AU)