Intelligent coating based on metal-insulator transitional Ti3O5 towards fire sensing and protection

With the acceleration of urbanization, energy-efficient, comfortable, and lightweight materials have been growing widely used. An ideal real-time monitoring strategy integrated with prominent fire sensing capability, flame retardancy, and embedded in communication network Internet of Things (IoT) remains a huge concern. Here, we develop a sensitive and durable fire alarm intelligent coating strategy based on a metal-insulator transitional Ti3O5 via a layer-by-layer assembly (LBL). We elucidate the atomic structure, electronic band, and orbital structure of Ti3O5 correlated from the charge-ordered β-phase (electrical insulation state) to valence-delocalized of α-phase (electrical conduction state) during switchable temperature by density functional theory (DFT) calculations. Accordingly, a thermally activated electron jump among the localized states facilitates the early fire alarm with a sensitive fire response time (∼3.78 s) and an excellent response repeatability. Moreover, the fire alarm coating also performs the remarkable flame retardancy, smoke suppression and weatherability. This work provides a promising routine to realize the condensed matter as advanced fire sensors, offering insights into fire alarm towards smart phones, cloud service, and a central control system through IoT for fire prevention and protection application.