Designing a novel targeted-release nano-container based on the silanized graphene oxide decorated with cerium acetylacetonate loaded beta-cyclodextrin (β-CD-CeA-MGO) for epoxy anti-corrosion coating

Abstract

For the first time, cerium acetylacetonate (CeA) was encapsulated in a novel controlled-release nano-carrier based on the beta-cyclodextrin (β-CD)/graphene oxide (GO) for effective mitigation of the metal corrosion. The outcomes of the FT-IR, XRD, Raman, and UV–Vis spectroscopies displayed successful interactions of the β-CD-CeA with the surface of GO nano-particles. Tafel curves proved that in the presence of the β-CD-CeA/modified GO (MGO) nano-particles, the corrosion current density of metal was diminished from 7.62 µA.cm−2 (for the uninhibited sample) to 0.08 µA.cm−2. The EIS results achieved in the solution phase studies demonstrated that the total resistance (Rt) increased from 1469 Ω.cm2 (for the uninhibited sample) to 12083 Ω.cm2 (nearly 88% efficiency) after 48 h of exposure. The observations derived from FE-SEM, EDS, and mapping investigations confirmed the formation of anti-corrosive film over the metallic substrate in the solution phase. After nano-particles incorporation into the epoxy (EP) matrix, the EIS evaluations from the scratched EP revealed that the Rt increased from 19430 Ω.cm2 (for neat EP) to 59817 Ω.cm2 after 24 h of exposure to the 3.5% NaCl solution, evidencing the effective corrosion inhibition characteristics of the designed composites. Besides, the FE-SEM and EDS/mapping analyses ensured that the defected zone of the epoxy coating was protected with a highly dense inhibitive film. EIS measurements clarified that the corrosion resistance of the intact neat EP coating (92 MΩ.cm2) improved significantly after the incorporation of β-CD-CeA-MGO particles (~5840 MΩ.cm2), demonstrating the coating barrier performance enhancement. Furthermore, the DFT modelings strongly affirmed the CeA and β-CD affinity towards the epoxy resin.