Polyimide Aerogel Fibers with Controllable Porous Microstructure for Super-Thermal Insulation Under Extreme Environments

Application of aerogel fibers in thermal insulating garments have sparked a substantial interest. However, achieving a high porosity and low thermal conductivity for aerogel fibers remain challenging, despite the innovative designs of porous structure. Herein, we fabricated lightweight and super-thermal insulating polyimide (PI) aerogel fibers via freeze-spinning by using polyvinyl alcohol (PVA) as a pore regulator. The high affinity of PVA with water enables it to accelerate the ice crystal nucleation, adjust pore formation, and construct a controllable porous structure of PI aerogel fiber. The as-fabricated PI aerogel fiber has a considerable reduced pore size, high porosity (95.6%), improved flexibility and mechanical strength, and can be woven into fabrics. The PI aerogel fabric exhibits low thermal conductivity and excellent thermal insulation in a wide range of temperature (from − 196 to 300 °C). Furthermore, the PI aerogel fabrics can be easily functionalized to expand their applications, such as in intelligent temperature regulation and photothermal conversion. These results demonstrate that the aerogel fibers/fabric are promising materials for next-generation textile materials for personal thermal management.Graphical abstract