Cationic Reduced Graphene Oxide as Self-Aligned Nanofiller in the Epoxy Nanocomposite Coating with Excellent Anticorrosive Performance and Its High Antibacterial Activity

The design and preparation of an excellent corrosion protection coating is still a grand challenge and is essential for large-scale practical application. Herein, a novel cationic reduced graphene oxide (denoted as RGO-ID⁺)-based epoxy coating was fabricated for corrosion protection. RGO-ID⁺ was synthesized by in situ synthesis and salification reaction, which is stable dispersion in water and epoxy latex, and the self-aligned RGO-ID⁺-reinforced cathodic electrophoretic epoxy nanocomposite coating (denoted as RGO-ID⁺ coating) at the surface of metal was prepared by electrodeposition. The self-alignment of RGO-ID⁺ in the coatings is mainly attributed to the electric field force. The significantly enhanced anticorrosion performance of RGO-ID⁺ coating is proved by a series of electrochemical measurements in different concentrated NaCl solutions and salt spray tests. This superior anticorrosion property benefits from the self-aligned RGO-ID⁺ nanosheets and the quaternary-N groups present in the RGO-ID⁺ nanocomposite coating. Interestingly, the RGO-ID⁺ also exhibits a high antibacterial activity toward Escherichia coli with 83.4 ± 1.3% antibacterial efficiency, which is attributed to the synergetic effects of RGO-ID⁺ and the electrostatic attraction and hydrogen bonding between RGO-ID⁺ and E. coli. This work offers new opportunities for the successful development of effective corrosion protection and self-antibacterial coatings.