Autonomous Damage Detection in Multilayered Coatings via Integrated Aggregation-Induced Emission Luminogens

Detection and assessment of small-scale damage at early stages are essential for polymeric materials to extend lifetime, avoid catastrophic structural failure, and improve cost-efficiency. Previous self-reporting coatings provide visual indication of surface damage but have been limited to a single layer without information on the depth of crack penetration. Here, we present a novel strategy for autonomous indication of damage in multilayered polymeric materials using aggregation-induced emission luminogens (AIEgens). Three different AIEgens are encapsulated and layered into polymeric coatings. When scratches of varying depths penetrate the coating layers, different combinations of AIEgens are activated to visually detect the depth of damage based on the corresponding fluorescent colors. The AIEgen-based detection mechanism makes this system a powerful tool for damage indication in a variety of polymeric coatings.