Layer-by-layer assembled sulfonated-graphene/polyaniline nanocomposite films: enhanced electrical and ionic conductivities, and electrochromic properties

In this article, we report the facile synthesis of sulfonic acid-grafted reduced graphene oxide (S-rGO) using a one-pot method under mild conditions, and layer-by-layer (LbL) assembly and electrochromic properties of S-rGO/polyaniline (S-rGO/PANI) nanocomposite thin films. It was found that the multilayer films of S-rGO/PANI exhibit much faster electrochromic switching kinetics than that of corresponding spin-coated PANI thin films. The enhancement can be attributed to the drastically increased electrical and ionic conductivities of the S-rGO/PANI films brought by the graphitic structure of the S-rGO sheets and the sulfonic acid groups attached to S-rGO, which lead to non-diffusion-controlled redox processes of PANI.