A smart platform for monitoring the whole life-course of self-healing coatings with the cooperation of self-reporting microcapsules and coating matrix

Abstract

Constructing a smart system with the capability to self-report the whole life-course of self-healing coatings, containing damage, self-healing, and restoration of protection capability after maintenance of large-scale damages, is a formidable challenge. In this study, we propose a facile strategy to address this issue by developing an intelligent platform using acrylic coating containing pH-responsive microcapsules loaded with phenolphthalein indicator. Upon damage, the color probes are released from the microcapsules and turn pink to locate cracks due to increased pH in the cathode region. The smart platform enables the sequencing of anticorrosion dynamics for various self-healing coatings as the slender pink color resulting from the low hydroxide ion generation rate signals the high anticorrosion efficiency. The highest-performance coating containing smart microspheres loaded with cerium acetate as corrosion inhibitors was easily screened, which was validated using electrochemical impedance spectroscopy (EIS). Furthermore, the hydroxide ions generated during electrogalvanic reactions could be consumed by coating matrix of acrylic resin through ester hydrolysis after repairing cracks. Hence, smart platform can be employed to evaluate the restoration of coating protection by monitoring the disappearance of the pink color. This facile yet effective strategy exhibits tremendous potential for real-time monitoring of the entire life-cycle and rapid screening of excellent self-healing coating formulations.