In situ crosslinking of mechanically robust waterproof and moisture permeable cellulose diacetate nanofiber aerogels for warm clothing

In the present study, an ultralight, super-flexible, waterproof, and breathable aerogel with low thermal conductivity is produced by crosslinking hybrid nanofibers of cellulose diacetate (CA) with an aqueous blocked isocyanate crosslinker (BIC) in situ. The mechanical properties of the hybrid nanofiber aerogel (HNFA) can be tuned by adjusting the BIC/CA ratio while retaining its thermal conductivity (27.2–28.4 mW·m−1·K−1) and porosity (99.25%–99.36%). The HNFA has super-elastic at ultralow temperatures (−196 °C), good compressive fatigue resistance, outstanding bending resistance (it is capable of withstanding 20,000 bending cycles), favorable breathability, and water resistance (contact angle: 162°). Therefore, it is a promising material for warm clothing for use in extreme environments.