Synthesis and characterization of metal ion end capped nanocontainer loaded with duo green corrosion inhibitors

For the first time, two green corrosion inhibitors are loaded into the halloysite nanotubes (HNT) and end capped using metal ions. Vanillin and thyme oil were loaded into HNT and end capped using copper ions to form VTHNT-ES. The loading of the HNT with the duo green corrosion inhibitors were characterized by ultraviolet visible spectroscopy (UV–vis) and confirmed by the peaks of vanillin, thyme oil and HNT in the Fourier-transform infrared (FTIR) spectroscopy spectrum. The morphology of the nanocomposite at each stage were observed using field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The loading efficiency was calculated up to 900 °C. VTHNT-ES exhibited loading efficiency than the unsafe nanocontainers loaded with artificial corrosion inhibitors currently used in smart coatings. The release of the duo corrosion inhibitors from the VTHNT-ES was studied using UV–vis. Vanillin remained intact in water, whereas only 3.7% of the total thyme oil present in VTHNT-ES was released for a time period of 100 h. The sudden increase in release upon the introduction of sulphuric acid proved that the VTHNT-ES are highly sensitive to pH.