An investigation on the corrosion behavior of the epoxy coating embedded with mesoporous silica nanocontainer loaded by sulfamethazine inhibitor

[Display omitted] •Mesoporous silica acted as the host of sulfamethazine as inhibitor.•Corrosion inhibitor released from nanocontainer in response to corrosion damage.•Corrosion resistance of coatings with MSInh was improved due to inhibitor release.•Sulfamethazine could link to d-orbital of iron and raise the corrosion resistance. In this study, mesoporous silica served as the host for an eco-friendly corrosion inhibitor. This material could adsorb and release corrosion inhibitor in different aqueous media. A composite coating was prepared by embedding 1 wt. % mesoporous silica loaded with sulfamethazine (MSInh) as the corrosion inhibitor into the epoxy film to protect mild steel as substrate. Anti-corrosion properties of the solution containing MSInh and corrosion protection function of composite coating were assessed by electrochemical impedance spectroscopy. Results showed the higher corrosion protection of epoxy/mesoporous silica loaded with inhibitor (MSInh) in NaCl solution for one month of immersion in comparison with epoxy/mesoporous silica and epoxy coatings. Charge transfer resistance of epoxy, epoxy/MS, and epoxy/MSInh after 30 days of immersion estimated 6, 15, and 80 kΩ cm2, respectively. The results revealed the higher corrosion resistance of epoxy/MSInh which confirmed the barrier effect of mesoporous silica against corrosive species and corrosion inhibiting effect of the released sulfamethazine molecules.