Rabbit-hair-like SiO2/PI composite nanofibers with super durability for thermal insulation

Flexible composite membrane with strong strength and good thermal performances simultaneously are highly desired in broad fields. Herein, rabbit-hair-like silica/polyimide (SiO 2 /PI) composite nanofibers with super durability are prepared by a simple electrospinning and impregnating process. The embedded hollow SiO 2 microspheres and the bamboo-shaped hollow structure of the composite nanofibers endow the membrane with excellent thermal insulation , while the externally coated thin PI layer provides quite high strength without significantly reducing its thermal stability. The obtained SiO 2 /PI composite membrane demonstrates high tensile strength (19.7 MPa), good flexibility (withstanding dynamic bending at least 20000 cycles), low thermal conductivity (18.7–42.8 mW m −1  K −1 ), multi-cycle friction resistance (500 cycles) and abrupt hot/cold alternation stability (near 400 °C). These excellent properties are mainly attributed to the 3D bonding network of the composite membrane and the impregnating-reinforcing effect on single SiO 2 nanofiber. This composite membrane not only overcomes the low tensile strength and poor durability of pure SiO 2 membrane, but also possesses lightweight and fireproof properties, demonstrating broad prospects in thermal insulation, anti-shock of fire/cold and wearable protective fabrics.