Isomerism-Enabling Low-Temperature Ultrasensitive and Moisture-Resistant Fire-Alarming “Guarder” via Color Changing

Aiming to integrate a low-temperature, ultrasensitive and wireless remote-monitoring fire alarming with a fire suppression into a commercialized system, in view of a heat-induced tailored isomerization of Salen molecules and sunflower configuration for a heat capturing, we constructed a quasi-core-shell MAPP@Salen with silaned ammonia polyphosphate guiding a vertical deposition of Salen lamellas assembly. Resultantly, MAPP@Salen demonstrated an ultralow triggering temperature of 120 °C and 1 s time at 250 oC with a remarkable color from yellow to dark red. A Salen isomerization and its vertical alignment on MAPP accounted for an ultra-sensitiveness feature. A model acrylic coating with MAPP@Salen presented a 0.3 s responsive time at 250 °C as well as instant (0.5 s) and unstopped warning once flame approached. A wireless signal communication system via a color recognition algorithm and 4G IoT was realized. Additionally, the coating provided >10 min and ultrastrong intumescent fire protection via a Salen-participative charring optimization as well as well-persevered structural integrity after a long-term water attack. The fire-alarming capability was retained as well. This work pertaining to a bio-inspired hierarchical assembly integrates a low-temperature ultra-sensitive fire alarming and an optimized fire resistance for commercial all-time-scale fire retardants in multi-scenario universal applications.