Preparation and characterization of sodium carboxymethyl cellulose/silk fibroin/graphene oxide nanocomposite films

Biopolymer nanocomposite films were prepared by adding graphene oxide (GO) and reduced GO (RGO) to sodium carboxymethyl cellulose (CMC)/silk fibroin (SF) matrix. GO and RGO nanoparticles were prepared by a top-down method from graphite powder. This method consists of graphite oxidation followed by sonication, producing GO nanosheets. Then, RGO nanoparticles were obtained by chemical reduction of these nanosheets. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirmed the chemical oxidation and the formation of GO and RGO nanoparticles. The topography of as prepared films was characterized by atomic force microscopy (AFM) measurements, showing that the films have smooth surfaces with very low average roughness for both nanocomposites filled with GO and RGO. Furthermore, the thermal stability, glass transition temperature and surface roughness of the nanocomposite films were gradually increased with the incorporation of RGO. Consequently, RGO was shown to be a promising nanoparticle for biopolymer matrices to improve the thermal stability and the interface adhesion.