A silicone adhesive with ultralong room-temperature phosphorescence for direct damage visualization

Visual detection of early-stage microdamage is crucial for structural health monitoring to avoid catastrophic failures and extend equipment durability. However, current detection approaches are hampered by complex multi-component formulations and harsh operational requirements, making facile in situ microdamage visualization challenging. Herein, we report a novel room temperature phosphorescent adhesive (RTPA) via dynamic B-O bonds, achieving persistent phosphorescence emission in commercial adhesive systems. The resulting RTPAs exhibit ultralong phosphorescence lifetimes (up to 1.931 s) under ambient conditions, surpassing those of all reported RTP-based adhesives. As a silicone-based adhesive, the RTPA possesses versatile adhesion capability for various substrates, ranging from metals, inorganic compounds to polymers. More importantly, leveraging ultralong-lived phosphorescence emission in the dark, RTPAs enable in situ visual detection of microdamage in bonded substrates such as glasses. Therefore, such advantages make RTPAs promising candidates for damage visualization, anti-counterfeiting adhesives and information encryption.