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[Display omitted] • A multifunctional smart fireproof aerogel was fabricated with polyimide and MXene. • The aerogel could trigger the fire-alarm system within 5 s when being burned. • The aerogel exhibited high fire safety and self-extinguished within 1 s. • The aerogel could monitor temperature change in real time. • The aerogel showed excellent mechanical and piezoresistive sensing performance. Multifunctional smart fire-protection aerogels are urgently needed to meet the requirement of the Internet of Everything era. Herein, we fabricated a mechanically robust and high fire-safe polyimide/MXene composite aerogel (denoted as PI@MXene) with sensitive temperature-sensing and fire-warning capability. Thanks to the unique thermoelectric effect and high electrical conductivity of the 2D transition metal carbide (MXene) nanosheet, PI@MXene exhibited a linear relationship between the thermoelectric voltage and the temperature difference, showing sensitive temperature-sensing capability. When being burned, it could repeatedly trigger the fire-warning system in less than 5 s. More importantly, owing to the lamellar barrier and skeleton supporting effect of the MXene nanosheets, PI@MXene exhibited excellent flame retardancy, which self-extinguished within 1 s after exposing to a flame for 60 s and whose peak heat release rate was significantly decreased by 78% compared with PI aerogel. Besides, PI@MXene showed impressive thermal insulation, outstanding thermostability and durable piezoresistive sensing. This work provides a novel strategy to fabricate next-generation multifunctional fireproof aerogel, showing promising applications in intelligent robots, aerospace, and railway transportation. [ABSTRACT FROM AUTHOR]

Multifunctional biomass-based aerogels with mechanically robust and high fire safety are urgently needed for the development of environmentally-friendly intelligent fire fighting but challenging. Herein, a novel polymethylsilsesquioxane (PMSQ)/cellulose/MXene composite aerogel (PCM) with superior comprehensive performance was fabricated by ice-induced assembly and in-situ mineralization. It exhibited light weight (16.2 mg·cm−3), excellent mechanical resilience, and rapidly recovered after being subjected to the pressure of 9000 times of its own weight. Moreover, PCM demonstrated outstanding thermal insulation, hydrophobicity and sensitive piezoresistive sensing. In addition, benefiting from the synergism of PMSQ and MXene, PCM displayed good flame retardancy and improved thermostability. The limiting oxygen index of PCM was higher than 45.0 %, and it quickly self-extinguished after being removed away from fire. More importantly, the rapid electrical resistance reduction of MXene at high temperature endowed PCM with sensitive fire-warning capability (trigger time was less than 1.8 s), which provided valuable time for people to evacuate and relief. This work provides new insights for the preparation and application of the next-generation high performance biomass-based aerogels. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional fire protection nanocoating (MFNC) was constructed via layer-by-layer. • MFNC exhibited accurate temperature-sensing performance. • MFNC could trigger the fire alarm less than 4 s when being burned. • MFNC exhibited outstanding flame retardancy and good self-healing performance. • MFNC showed good piezoresistive sensing capability. The development of flame-retardant coating with sensitive fire warning is imperative but highly challenging in the "Internet of Everything Era". In this study, a multifunctional fire protection nanocoating (MFNC) was fabricated on the surface of flammable materials by dip-coating Ti 3 C 2 T X (MXene), montmorillonite (MMT) nanosheet, and 2-ureido-4[1H]-pyrimidinone-containing cellulose (UPC) via layer-by-layer assembly. The MXene/UPC layer endowed the nanocoating with accurate temperature sensing capability because of the outstanding conductivity and unique thermoelectric characteristic of MXene. When being burnt, MFNC was able to trigger the fire-warning system in less than 4 s. Owing to the MMT/UPC layer, MFNC showed excellent flame retardancy due to the barrier and catalytic carbonization of MMT. MFNC led to the increase in the limiting oxygen index of the flammable materials by up to 40.0% and the vertical burning test reached the UL94 V-0 rating. More importantly, attributed to the multiple hydrogen bond interactions of UPC, MFNC displayed good self-healing capability. Its fire-warning performance could quickly recover after being damaged. Furthermore, MFNC exhibited sensitive piezoresistive sensing ability, which makes it a promising candidate for application in firefighter motion detection. Our work provides new insights into the fabrication and application of multifunctional smart and efficient fire-protection coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional fire protection nanocoating (MFNC) was constructed via layer-by-layer. • MFNC exhibited accurate temperature-sensing performance. • MFNC could trigger the fire alarm less than 4 s when being burned. • MFNC exhibited outstanding flame retardancy and good self-healing performance. • MFNC showed good piezoresistive sensing capability. The development of flame-retardant coating with sensitive fire warning is imperative but highly challenging in the "Internet of Everything Era". In this study, a multifunctional fire protection nanocoating (MFNC) was fabricated on the surface of flammable materials by dip-coating Ti 3 C 2 T X (MXene), montmorillonite (MMT) nanosheet, and 2-ureido-4[1H]-pyrimidinone-containing cellulose (UPC) via layer-by-layer assembly. The MXene/UPC layer endowed the nanocoating with accurate temperature sensing capability because of the outstanding conductivity and unique thermoelectric characteristic of MXene. When being burnt, MFNC was able to trigger the fire-warning system in less than 4 s. Owing to the MMT/UPC layer, MFNC showed excellent flame retardancy due to the barrier and catalytic carbonization of MMT. MFNC led to the increase in the limiting oxygen index of the flammable materials by up to 40.0% and the vertical burning test reached the UL94 V-0 rating. More importantly, attributed to the multiple hydrogen bond interactions of UPC, MFNC displayed good self-healing capability. Its fire-warning performance could quickly recover after being damaged. Furthermore, MFNC exhibited sensitive piezoresistive sensing ability, which makes it a promising candidate for application in firefighter motion detection. Our work provides new insights into the fabrication and application of multifunctional smart and efficient fire-protection coatings. [ABSTRACT FROM AUTHOR]