Nano-scale P, Zn-codoped reduced-graphene oxide incorporated epoxy composite; synthesis, electronic-level DFT-D modeling, and anti-corrosion properties

The great potential of the advanced nano-materials like graphene oxide as smart containers for the controlled desorption of the inhibitors and their effectiveness as dual active/passive anti-corrosive agents in the polymeric composites has been noticed in recent researches. In this work, aminotrimethylene phosphonic acid (AMP) was used with two primary purposes: a non-toxic reductant of GO and a potent chelating agent. Zinc cations were chelated with AMP on the reduced graphene oxide, forming a nanocontainer with active protection potency. The successful reduction of GO and AMP-zinc chelation were confirmed by FT-IR, Raman, TGA, and UV-visible analysis. The interactions between GO, AMP, and zinc cations were investigated by density-functional theory (DFT)-D computational modeling. The electrochemical analyses have proved the inhibitory potency of the P, Zn-codoped reduced-graphene oxide (GAZ) nanoparticle. The incorporation of the anti-corrosive nanocontainers into the epoxy coating covered the defects of the matrix significantly. It resulted in great protection of the coating after 10 weeks of coatings evaluation in the NaCl media. It was also found that a dense and protective complex of AMP and zinc cations was formed in the scratched zone of the polymeric matrix. This protective complex demonstrated the self-healing anti-corrosion potency of the fabricated nanoparticles.