Delamination and self-assembly of layered double hydroxides for enhanced loading capacity and corrosion protection performance

Layered double hydroxides (LDHs) nanocontainers intercalating with corrosion inhibitors are considered as a great platform to deliver corrosion inhibitors to the corroding sites. However, the small interlayer spacing and strong interaction between hydrotalcite laminates and interlayer anions impede the loading of macromolecular species into LDHs via a conventional anion-exchange process. This work devises a new paradigm for the preparation of LDHs in corrosion protection. A new method combining delamination and self-assembly to increase the loading of the organic corrosion inhibitor -5-Methyl-1,3,4-thiadiazole-2-thiol (MTT) into LDHs is applied and exhibits remarkable corrosion protection effects. The SEM, EDS, TEM, XRD, XPS and FT-IR were used to characterize the LDHs and LDH nanosheets. UV-vis absorption spectra and thermogravimetric analysis (TGA) experiments indicate an enhanced loading of MTT which is slowly released to the chloride media. The electrochemical experiments indicate that the release of MTT from their LDHs host can efficiently inhibit the corrosion on the surface of mild steel in 3.5 wt% NaCl solution. Furthermore, surface analysis experiments were carried out to probe into the anticorrosion mechanism of LDHs.