Figure 1.

Schematic of the autonomous damage detection system. Core–shell microcapsules containing a dilute solution of AIE luminogen are embedded in a polymeric material. Mechanical damage causes microcapsules to rupture and release their liquid payload. Subsequent evaporation of the solvent causes solid AIE luminogen to deposit in the damaged region, which fluoresces under UV light. The core solutions contained within intact microcapsules remain nonemissive, providing excellent contrast between damaged and undamaged regions of the material.