Smart healable and reportable anticorrosion coating based on halloysite nanotubes carrying 8-hydroxyquinoline on steel

Integrating healable and reportable ability to sustain new-generation smart anticorrosion coatings with long-term durability is highly desirable to accommodate the development of marine industries. Herein, a new type of dual-function coating is designed to fulfill the needs. Through introducing the smart nanocontainers based on the core of HNTs loaded with 8-hydroxyquinoline (8HQ) and the shell made from sodium tripolyphosphate-chitosan (CS) into conventional epoxy matrix, the smart healable and reportable anticorrosion coating on carbon steel (Q235) was developed. Electrochemical impedance spectroscopy (EIS) and salt spray measurement indicated the corrosion inhibition effect of the nanocontainers and healable performance of composite coatings. Benefitting from the 8HQ, the designed waterborne epoxy coating displayed higher low-frequency modulus after 60 days of immersion, confirming the long-term protection ability. Besides, the composite coating exhibited obvious dark-green color at damaged region to timely sense and report the local corrosion in 30 min of immersion tests. This smart coating with sensitive corrosion visualization and well-performed healable properties holds great potential in actual anticorrosion fields.