Multifunctional MXene-based fire alarm wallpaper with sandwich-like structure for enhanced fire safety and prevention

Design and development of multifunctional fire-resistant and fire alarm wallpaper (FAW) that can simultaneously hold early fire warning function and the ability to inhibit flame propagation is urgently required to boost the fire safety of combustible materials in public security. Herein, a flexible sandwich-like and nacre-biomimetic FAW was fabricated by using renewable lignocellulose nanofibrils (LCNF) and MXene thermosensitive sensor via a vacuum-assisted alternate self-assembly method. The FAW achieved ultrasensitive fire early warning response because of the synergistic effect of the insulating LCNF layers and highly conductive MXene with hierarchical structure sandwiched between LCNF layers. Furthermore, owing to the ultrafast catalytic char formation and intumescent flame retardant effect of ammonium polyphosphate (APP), the trigger sensitivity and thermal oxidation capacity of the FAW (LCNF-15) were greatly optimized by adding 15 % APP in the LCNF layer, resulting in a superior fire alarm response (0.32 s) and a continuous alarm signal (about 3073.0 s) under a flame attack. Besides, the LCNF-15 also exhibited good flexibility, ideal cyclic warning performance, excellent heat insulation ability and strong char-forming properties in a fire. The sandwich-like strategy offers a new platform for the construction of MXene-based multifunctional FAW, which is of great value in broadly addressing the fire hazard problem of traditional wallpapers.