Enhancement of barrier protection of organic coatings with the incorporation of graphene oxide as a reinforcing filler

Abstract

Graphene and its derivatives, such as graphene oxide (GO) are new materials with unique properties which have been widely employed as a reinforcing filler material in organic coatings. The superior properties of GO, such as its large surface area, surface wettability, stability, chemical resistance, and high mechanical strength, have resulted the GO material to be a promising additive in anti-corrosion coatings. On the other hand, due to the presence of oxygen-containing functional groups, the GO has exhibited high water dispersibility. In addition, the chemical functionalization that is facilitated by these functional groups on the GO surface resulted in the enhancement of dispersibility and corrosion protection performance. Hence, the GO-based polymer coatings have attracted significant attention globally especially in the corrosion industry. Although, the electrochemical characteristics of GO-polymer nanocomposite coatings have not been explored much. Therefore, in this study, a series of coatings were developed by incorporating various amounts of GO nanoparticles into the polymer matrix. These coatings were then coated on the steel substrates and the barrier protection performance of GO-based coatings was investigated using electrochemical impedance spectroscopy (EIS). In addition, the electrochemical activity was observed by determining the breakpoint frequencies ($f_b$) over a period of 90 days. The results revealed that the incorporation of GO nanoparticles significantly enhanced the corrosion protection performance of the coatings. The results demonstrated that the best corrosion resistance was achieved by the 0.5 % GO coating sample. Fourier transform infrared (FTIR) spectroscopy was employed to verify the chemical structure of the composite coatings.