Dual-functional graphene oxide-based nanomaterial for enhancing the passive and active corrosion protection of epoxy coating

The poor dispersion and compatibility of graphene oxide (GO) in epoxy resins, and the lack of active corrosion protection of epoxy coating containing GO will greatly limit its applications in the field of corrosion protection. Here, we prepared dual-functional GO-based (GAS) nanomaterial, which can be evenly dispersed in epoxy coating and can create covalent bonds with epoxy resins through ring opening reaction (function one). The improvement in dispersion and compatibility enhances the impermeability of epoxy coating (passive corrosion protection). In addition, the prepared GAS nanomaterial can also be used to load corrosion inhibitor 2-mercaptobenzothiazole (MBT) and achieve pH-responsive release (function two), which can provide active corrosion protection for epoxy coating. Electrochemical impedance spectroscopy (EIS) results show that self-healing efficiency (eta self-healing) of the defected epoxy coating containing MBT-loaded GAS nanomaterial (GASM-Coat) changes from a negative value to a positive value after 24 h of immersion, which is attributed to the excellent self-healing properties of GASM-Coat. The combination of passive and active corrosion protection makes GASMCoat achieve long-term corrosion protection of metal substrates.