Real-Time Assessment of Mechanical Integrity in Self-Healing Polymers

Polymers with programmed functionalities have been invented to autonomously detect and repair the mechanical damage. Although the traditional self-healing ability will theoretically increase material lifetime and safety, the lack of a self-assessment mechanism raises challenges in practical implementation. The conventional self-healing polymers provide no information about their mechanical and functional status, making it difficult to evaluate if the damage has been repaired and whether the self-healing ability is still in place to resist the next mechanical impact. In this work, we report a multifunctional material system that not only self-heals the mechanical damage but also reports its structural integrity in real-time. Microcapsules containing aggregation induced emission (AIE) luminogens-embedded healing reagents are incorporated into a polymeric material. The self-healing function is correlated with an evolution in emission wavelength, where the damage occurrence, healing process, and full recovery are characterized by distinctive fluorescence colors. This integrated self-healing and self-assessment ability significantly increases the sustainability and reliability of a wide range of polymeric materials and demonstrates a general concept of designing mutual communications among diverse stimuli-responsive functionalities.