Fabrication and applications of polyimide nano-aerogels

Nano-aerogels have been used in various fields due to their ultralow density, ultrahigh porosity and ultralow thermal conductivity. However, common nano-aerogels with poor thermal stability are scarcely used in high- and low-temperature environments. Polyimide (PI) nano-aerogels that are developed from PIs can meet the requirements and have been studied in recent years, especially in the field of deep space exploration. In this review, we discuss the current state of the fabrication, classification, methods of improving properties and fields of application of the PI nano-aerogels. As one of the best materials with outstanding comprehensive properties under harsh temperature environments, PI nano-aerogels will play important roles in technology in the future.