Synthesis of nanosensors for autonomous warning of damage and self-repairing in polymeric coatings.

Polymeric materials are susceptible to minor damage, which is undetectable. Without timely and effective repair treatment, the damage may deteriorate the integrity of the materials and ultimately result in material failure and catastrophe. Autonomous warning and simultaneous damage repair are of great practical significance yet difficult to realize. Herein, we introduce a smart coating with autonomous warning and repairing of damage by the simple incorporation of nanosensors embedded with phenanthroline as a corrosion indicator and inhibitor. The electrochemical corrosion resulting from coating damage can be rapidly indicated by a prominent orange-red color in just five minutes. In addition to the warning function, the smart coating exhibits efficient self-repairing in the defective region, as reflected from the disappearance of the electrochemical admittance peak. This simple and powerful strategy dependent on a single active component to achieve an autonomous warning and repairing effect is highly expected to provide a new avenue for enhancing the security and longevity of other polymeric materials.