A review on polyimide-based structures for regulating the electromagnetic absorption and reflection

The research of multifunctional materials capable of maintaining stable shielding performance has become crucial to safeguard the operational integrity of aerospace systems. Incorporating conductive and magnetic fillers into heat- and chemical-resistant polyimide, combined with innovative structural design, has become a research hotspot for preparing electromagnetic shielding and stealth conductive composites with efficient electromagnetic absorption and reflection properties. This review provides the first systematic summary of the research on polyimide-based electromagnetic shielding and stealth composite materials. It firstly introduces electromagnetic shielding mechanisms of reflection, absorption and multiple reflection as well as key performance indicators such as conductivity, electromagnetic interference shielding efficiency and power coefficient. Then the review focuses on the design and preparation strategies of polyimide-based shielding materials with different structures as films, foams and fabrics. Through collaborative design of carbon-based materials, metal nanoparticles and hybrid fillers, and combined with structural innovations in sandwich, multilayered and Janus asymmetric architectures, researchers have achieved breakthrough enhancement in the shielding and stealth performance of composites by controlling interfacial impedance matching and the electromagnetic propagation trajectory. Finally, the review also discusses the future opportunities and challenges of polyimide-based composite materials for broadband electromagnetic absorption capabilities in aerospace stealth technologies.