Enhanced thermal insulation of polyimide aerogels in extreme environments tailored by rigid-flexible coupling synergy

In extreme environments, thermal insulating materials must exhibit superior mechanical properties, be waterproof, and possess thermal stability to ensure optimal protection for both the human body and equipment. However, most existing thermal insulating materials suffer from limited thermal insulation performance, moisture absorption, inferior mechanical properties, and suboptimal thermal stability, thereby limiting their ability to protect against extreme conditions. In this study, the combination of electrospinning and freeze-drying technology was used to prepare polyimide aerogels with a rigid-flexible coupling structure. The prepared polyimide micro/nanofibrous aerogels demonstrated ultralight performance (6.5 mg cm −3 ), significant compression performance, and the ability to recover to their initial state under 80 % strain. After 1000 compression cycles at 60 % strain, only 7.2 % plastic deformation was observed, indicating excellent fatigue resistance. The synergistic effect of the rigid-flexible coupling endowed the aerogel with superior thermal insulation (26.9 mW m −1 K −1 ), and high-temperature resistance (441.8 °C). Furthermore, surface modification with water-repellent agents imbued the aerogels with enhanced hydrophobicity, making them suitable for use in extreme environments such as rainwater. This work offers new insights for the design and development of high-performance insulation materials in extreme conditions.