Self-sensing polymeric materials based on fluorescent microcapsules for the detection of microcracks

In this study, self-sensing materials have been developed owing to their ability to indicate material damage through an evident optical signal. For this, fluorescent core–shell microcapsules were synthesized by in situ polymerization in an oil-water emulsion. These microcapsules, embedded in a black epoxy resin, release a revealing substance during damage processes that allow microcracks detection in the material. The morphology, chemical structure, size distribution, thermal stability and mechanical properties of the fabricated microcapsules were characterized. Furthermore, the mechanical and optical characterizations of the composite were performed. As result, it has been shown how the microcracks cannot be observed under visible light but it was possible to identify and detect them under a conventional 254 nm ultraviolet (UV) lamp, introducing an additional functionality in the material for damage detection/monitoring.