Spontaneously self‐healing silicone polyurea coating for metal corrosion protection

Abstract Organic anticorrosion coatings (OACs) are the most effective, economical, and environmentally friendly protection strategy for metals. However, the traditional OACs usually inevitably suffer mechanical cracks during their service life. If not repaired in time, the resultant cracks in OACs will result in irreparable corrosion of the metal substrate. More detrimentally, these microcracks are not easily detectable at the initial stage. If OACs can autonomously heal their damage at the initial stage, the microcracks will be repaired in time and the metal substrate will be protected well. Thus, giving OACs the self‐healing capability is a promising strategy for metal protection. Herein, an autonomously self‐healing TiO 2 ‐reinforced silicone polyurea (SPU‐ g ‐TiO 2 ) elastomer was successfully designed as anticorrosion coating for Q235 carbon steel (QCS) protection. The SPU‐ g ‐TiO 2 elastomer matrix exhibited excellent stretchability with a maximum strain of 3826.72% and fast self‐healing ability with an outstanding self‐healing efficiency of 98.69% for 6 h without any external stimulus at room temperature. The QCS coated with SPU‐ g ‐TiO 2 showed excellent damage resistance and good anticorrosive ability, and it can self‐heal the microcracks generated in its coating in time to prevent corrosive media corroding the internal mental substrate. This work has a positive guiding significance for the development of functional OACs to improve their protection for metallic materials. Highlights A bionic smart self‐healing SPU‐ g ‐TiO 2 coating was successfully synthesized. The mechanical and self‐healing properties are balanced using nanoparticles. The coating features excellent self‐healing capability and stretchability. Q235 steel coated with SPU‐ g ‐TiO 2 shows good anticorrosive ability.