Preparation and comparative study of anticorrosion nanocomposites of polyaniline/graphene oxide/clay coating

In this study, novel anticorrosion coatings including doped polyaniline, reduced graphene oxide (RGO) and modified clay sodium montmorillonite (Na-MMT) were synthesized. The nanocomposite particles were coated on carbon steel after optimal mixing and dispersion in epoxy resin. In order to increase the dispersibility and increase the functional groups between the graphene plates, the initial graphene oxide nanoparticles were re-oxidized and finally reduced to have a better dispersibility in the composite environment. Sodium dodecyl benzene sulfonic acid (SDBS) was used as a secondary dopant and surfactant. Synthesized nanocomposites were characterized using Fourier-transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Furthermore, Open Circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS), Fourier-transform infrared spectroscopy (FFT), and salt spray test were used to investigate the electrochemical and anticorrosion behavior of the synthesized composite. The results showed that the initiative of adding certain ratios of RGO and Na-MMT to the polyaniline polymer significantly increased the anticorrosion properties of the coating. It was also found that at the same part ratios, the anticorrosion property of RGO is higher than the anticorrosion property of Na-MMT. According to the Tafel test, the corrosion current of the synthesized nanocomposite was 0.065 μA cm−2, which was lower than the corrosion current of other samples and shows the superiority of the anticorrosion property of this sample. Also, after 720 h of Salt spray test (In 3.5% wt NaCl), a very high and desirable durability of this sample (Sample a) has been observed.