High fire safety thermal protective composite aerogel with efficient thermal insulation and reversible fire warning performance for firefighting clothing

High fire safety thermal protective aerogels serve as a thermal insulation barrier in firefighting clothing are urgently needed to improve personal protective technology. However, fabricating fire protection aerogels that can simultaneously hold efficient insulation and early fire warning capabilities to provide high fire safety for firefighters still remains grand challenging. Herein, a novel lightweight and high fire safety smart thermal protective composite aerogel (APFP) composed of aramid nanofibers (ANFs), polyethylene glycol (PEG), Fe3O4 NWs, and polyaniline (PANI) was fabricated via freeze-drying and a chemical in-situ polymerization method. The resultant APFP achieved an efficient thermal buffer performance in response to high temperature with a latent heat of 162.5 J/g due to the absorption and storage thermal capability of PEG. Furthermore, based on the resistance change of Fe3O4 NWs under high temperature and flame, adding 25 wt% Fe3O4 NWs to ANFs-based aerogel, APFP aerogel can achieve resistance sensitive transition from an electrically insulated state to a highly conductive state. Under a flame attack, the APFP demonstrated an ultrasensitive and repeatable fire warning response (1.3 s), which contributes to acquiring active fire protection for APFP before the thermal barrier layer malfunctions in fire. In addition, the APFP exhibited impressive flexibility, heat insulation, lightweight, and flame retardancy, which self-extinguished within 1.5 s after exposure to fire for 10 s. This work proposed an ingenious strategy for the construction of high fire safety and thermal insulation fireproof aerogels, which revealed enticing prospects as thermal insulation barrier in the field of firefighting clothing.