Corrosion control by autonomous self-healing epoxy coatings based on superabsorbent healing agents

Metallic corrosion is an all-time dangerous and extremely expensive problem. Here, we present an autonomous self-healing polymer coating based on an epoxy resin and superabsorbent polymer (SAP) blend as an anticorrosion coating. Tailor-made coatings were manufactured by controlling the location of the SAP on the surface, middle, and bottom of the coating. The corrosion behavior and self-healing process of the coatings were analyzed at the macro, micro, and sub-micro scales using Electrochemical Impedance Spectroscopy (EIS). The SAP preferentially located at the bottom showed coating resistance values higher than 1 x 1011 omega cm2 over 10 days of immersion with 3-point defects. This configuration provided the best anticorrosion performance, preventing coating delamination, and protecting the metal from corrosion after surface damage, indicating better barrier properties. The SAP enabled local repair of the crack when in contact with water, minimizing the diffusion of oxygen and electroactive species, which are responsible for the corrosion of a metal.