Ultralong Room-Temperature Phosphorescence Achieved by Microcapsule Rupture-Triggered In-Situ Polymerization for High-Contrast Damage Visualization and Advanced Anti-counterfeiting

Polymer materials exhibiting mechano-responsive ultralong room temperature phosphorescence (RTP) are highly desirable, yet it remains challenging to achieve. Herein, a microcapsule (MC) rupture-triggered in-situ polymerization strategy is introduced to realize mechano-responsive ultralong RTP with full-color tunable emissions. This approach involves co-encapsulating organic phosphors and moisture-reactive hexamethylene diisocyanate (HDI) within MCs, which are subsequently dispersed into a polymer matrix. Upon mechanical damage, the ruptured MCs release HDI. The liberated HDI then undergoes moisture-triggered polymerization, forming a rigid cross-linked network in-situ at the damage site. This network effectively suppresses non-radiative decay pathways of triplet excitons, thereby activating “turn-on” ultralong RTP signals specifically and exclusively at the damaged sites. The resulting system achieves ultralong RTP lifetimes exceeding 1.5 seconds and a phosphorescence quantum yield of 10.4%. Notably, these RTP systems demonstrate exceptional stability under harsh conditions, including immersing in neutral, acidic, alkaline aqueous environments and various organic solvents, as well as exposure to high temperatures. Full-color tunable afterglow emissions, ranging from blue to red, are readily achieved by employing different organic phosphors. This approach facilitates the development of self-healing smart coatings capable of high-contrast damage visualization, as well as advanced anti-counterfeiting systems featuring mechanically activated dynamic RTP responses. Furthermore, the compatibility of MCs with diverse polymer matrices significantly expands the practical applicability of stimuli-responsive ultralong RTP materials.