Novel bi-functional RGO-HPSE-Zn@epoxy nanocomposite with superior corrosion protection potency

[Display omitted] •A control-release anti-corrosion system based on RGO-HPSE-Zn was fabricated for epoxy coating.•RGO-HPSE-Zn showed superior active corrosion protection performance in the case of scratched coating.•The intact RGO-HPSE-Zn/EP coating represented the high impedance values of about 1010.5 ohm.cm2 after long time exposure. Recently, the employment of organic coatings (i.e. Epoxy resin (EP)), become common to provide immunity for metals in corrosive environments. The lack of self-healing/active protection in EP, as well as short-term barrier performance, inspired authors to provide superior barrier/self-healing protection potential for EP by designing a highly durable control-release system based on a novel composite metal–organic polymeric matrix. Therefore, in this work, first, the graphene oxide nanosheets were synthesized (GO), then reduced and also functionalized by the extracted bio-compatible organic-based molecules of Heracleum persicum seed (RGO-HPSE), and finally modified via zinc metal cations doping (RGO-HPSE-Zn). The successful synthesis of nano-pigments was characterized, applying a variety of analyses. Further, the electrochemical approaches were employed for solution-phase investigation and demonstrated 66% and 86% anti-corrosion capability for RGO-HPSE and RGO-HPSE-Zn, respectively. Afterward, 0.2 wt.% of nano-pigments were incorporated into the EP coating network to provide active self-healing performance and enhance the barrier behavior of the EP coating. Applying EIS technique, the coatings were evaluated in two forms of scratched and intact. The 83,973 ohm.cm2 and 122,412 ohm.cm2 of impedance values were achieved from the scratched RGO-HPSE/EP and RGO-HPSE-Zn/EP coatings, respectively, while the maximum impedance values of scratched neat EP was recorded at 35,673 ohm.cm2. The superior barrier performance of RGO-HPSE-Zn/EP intact coating was achieved through negligible descend of |Z|10mHz value during 10 weeks of immersion (1010.5 ohm.cm2 → 1010.2 ohm.cm2).