Bionic coral-like PANI-modified graphene oxide for enhancing corrosion resistance of waterborne epoxy coatings: High barrier and self-healing properties

Herein, bionic coral-like PANI-loaded graphene oxide (GO@coral-like PANI) nanomaterials were successfully prepared by gas carbon formed by submicron calcium carbonate as a sacrificial template during the polymerization of PANI with graphene oxide. The unique bionic coral-like PANI outer layer not only enhances the passive barrier ability and dispersion stability of the GO nanosheets, but also provides self-healing capability to the composite coating through the ability to promote the oxidation of iron ions to Fe2O3/Fe3O4 and the loaded corrosion inhibitors (BTA and Ce ions). While the structure, morphology and properties of the GO@PANI/BTA/Ce (GPBC) nanocomposites have been systematically characterized, the barrier and self-healing properties of the composite coatings were tested by electrochemical, salt spray tests and corrosion product elemental analysis. The samples with GPBC exhibited an extended failure time of 30 d and an increased duration of 200 h in the salt spray test compared to pure WEC, as well as self-healing properties after 4 h of coating rupture. The results demonstrated that the WEC loaded with GPBC nanomaterials provides a long-lasting passive barrier effect and self-healing ability.