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 <i>in situ</i> microdamage visualization challenging. Herein, we report a novel room temperature phosphorescent adhesive (RTPA) <i>via</i> 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 <i>in situ</i> 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.