Polyaniline-modified graphene oxide nanocomposites in epoxy coatings for enhancing the anticorrosion and antifouling properties

Abstract

We report on the anticorrosion and antifouling properties of epoxy-based polyaniline (PANI)–graphene oxide nanosheets (GONs) paint coatings. PANI-based nanocomposites with different fractions of GONs were synthesized by an in situ polymerization process. Well-dispersed GONs were prepared using a modified Hummers’ method in the presence of (NH4)2S2O8 as an effective oxidant. We employed a spontaneous in situ polymerization at a constant temperature of 0°C using an ultrasonic bath to produce homogenous PANI-GON nanocomposites as characterized by X-ray diffraction (XRD), Fourier transfer infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FESEM) techniques. The nanocomposites were incorporated into an epoxy resin with different fractions to form epoxy/PANI-GON paint coatings. The epoxy/PANI-GON dip coated on a carbon steel (grade St-37) substrate exhibited significant improvement of the anticorrosion and antifouling properties. Epoxy-12 wt% PANI-GON coating revealed the highest corrosion resistance of 2.70 × 106 Ω cm2 after 192-h immersion in saline water measured by electrochemical impedance spectroscopy (EIS) technique. Such high corrosion resistance was attainable by inhibiting the diffusion process against the corrosive environment. Furthermore, higher protection against fouling was observed for epoxy 6 and 12 wt% PANI/GON as the most efficient antifouling composite coatings.