Efficient flame-retardant and multifunctional polyimide/MXene composite aerogel for intelligent fire protection

The rapid development of intelligent fire protection technology puts forward higher requirements for the versatility and fire safety of aerogels. Herein, a multifunctional fire-retardant polyimide/MXene/Ag2Se nanowires (PMA) composite aerogel was fabricated via freeze-drying and dip-coating. The PMA aerogel demonstrated good strength and flexibility. The improved thermoelectric properties of the PM1A1 aerogels were attributed to the energy filtration effect between the MXene and Ag2SeNW, which endowed the aerogels with accurate temperature sensing and sensitive, repeatable, and stable fire-warning performance. Even after 20 fire-warning test cycles, the trigger time was 4–8 s when exposed to the fire. Furthermore, in the vertical burning test, the PM1A1 aerogel demonstrated remarkable flame retardancy with a limiting oxygen index (LOI) as high as 53% and quickly self-extinguished. Meanwhile, the peak heat release rate of the PM1A1 aerogel was reduced by more than 65% compared with that of the PI aerogel. In addition, the PM1A1 aerogel also represented a good performance in thermostability and thermal insulation. And the sensitive piezoresistive sensing and controllable Joule heating performance enabled the aerogels to be used in wearable devices and heat management, respectively. After coated with polydimethylsiloxane (PDMS), the obtained PDMS-coated PMA aerogel exhibited superhydrophobic and self-cleaning performance. This work provides a facile approach to fabricate PI aerogel with high fire safety and multi-functions, showing promising applications in transportation, building, firefighting, and wearable devices.