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 struc-ture.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℃).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.