Molecular design of polyimide films for combating atomic oxygen erosion through combing experiments with simulations: A state-of-the-art review

Atomic oxygen (AO), as the primary component in the low Earth orbit (LEO), poses significant hazards to polymer materials. Polyimide, due to its excellent dielectric properties, mechanical strength, thermal stability, and radiation resistance, has become an ideal space polymer material widely used in LEO applications, which is prone to erosion caused by AO. To address this issue, various strategies have been employed to enhance PI's resistance against AO. Previous reviews on AO-resistant PI have primarily concentrated on experimental preparation methods, with relatively little emphasis on theoretical calculations and erosion mechanism. This review summarizes the research progress of both experiments and theoretical calculations on AO-resistant PI materials, with a specific focus on elucidating the rationale behind material design. Firstly, we introduce commonly used commercial PI films in the aerospace field. Secondly, we review experimental methods aimed at improving PI's ability to resist atomic oxygen, including protective coatings, blending and intrinsic modification approaches. Furthermore, our focus extends towards theoretical calculations of AO-resistant PI films, analyzing the underlying principles and mechanisms governing PI's capability to withstand atomic oxygen erosion. Finally, we present an extensive evaluation of different methods to enhance PI's resistance against AO and provide valuable suggestions and prospects for future developments in AO-resistant PI materials.