Rapid Self-Healing and High-Mechanical-Strength Epoxy Resin Coatings Incorporating Dynamic Disulfide Bonds

Smart materials with outstanding self-healing and reprocessable capabilities are highly desirable for next-generation coatings that can repair damaged coatings in a timely and autonomous manner. However, their prevalent use in practical applications is currently hindered by various limitations, such as low mechanical strength, long healing time, and expensive raw materials. Herein, we prepared a reprocessable epoxy resin coating (EP-SS-DAAX) with excellent self-healing and mechanical properties by incorporating dynamic disulfide bonds and flexible long chains into the resin network. The presence of flexible long chains promoted the mobility of molecular chains and the dynamic exchange of disulfide bonds, resulting in efficient self-healing and high toughness of the coating. EP-SS-DAA2 obtained a tensile strength of 33.30 MPa and a breaking elongation of 150.55% after 1 h of self-healing on the basis of achieving a high self-healing efficiency (93.68%) and can be reprocessed through hot-pressing with a tensile strength recovery rate of 107.03%. As a proof of concept, the healed coatings demonstrated excellent anticorrosive effects after being immersed in a 3.5 wt % NaCl aqueous solution for 7 days. This study provides a feasible approach to obtaining high-performance and reprocessable epoxy resins that have extraordinary integrated self-healing properties and mechanical performance.