Optical properties of polyaniline/modified graphene oxide nanocomposites

Abstract

In this research, the complex refractive index of polyaniline (PANI)/hexamethylene diisocyanate-modified graphene oxide (HDI-GO) nanocomposites has been obtained. The PANI/HDI-GO nanocomposites were prepared via in situ polymerization of aniline monomer in the presence of HDI-GO nanofillers, and their crystalline structure and surface morphology were investigated via X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements. Then, the experimental reflectance and transmittance for pure PANI and PANI/HDI-GO nanocomposite films with HDI-GO contents of 0.5, 1 and 2 wt% deposited on glass substrates were measured using UV-Vis spectrophotometry within the spectral region 300-900 nm. Then, the refractive index and extinction coefficient have been obtained using a novel method developed by the authors. The model is based on the generalized Scattering Matrix Method, which is used to obtain the theoretical values for the thin film/substrate reflectance and transmittance. Root mean square errors obtained are systematically lower than 0.21%, which corroborates the excellent accuracy of the model. The proposed method does not require sophisticated equipment, just a spectrophotometer, to obtain the complex refractive index of a thin film from transmittance and reflectance measurements.