Research of Radiation Tolerance via Polyimide Matrix Multilayer Dielectric Structures

Polyimide (PI), characterized by exceptional mechanical properties, high breakdown strength and excellent electron radiation resistance, are ideal substrates for spacecraft antennas in space applications. However, conventional PI film used in aerospace inevitably suffer from the harsh electron radiation environment in space, leading to performance degradation. This work designs a method to enhance the breakdown strength and electron irradiation resistance by constructing a sandwich structure incorporating mica nanosheets (MNNs). The PI-based composite film exhibited a significantly enhanced breakdown strength (657.07 kV/mm), a markedly improved tensile strength (129.8 MPa), and minimal performance loss after high-fluence electron irradiation (breakdown strength decreased by 5.9%, tensile strength decreased by 17.2%). The enhanced electron irradiation resistance can be attributed to the presence of high atomic number elements (Al, Si, K) in MNNs, which enhancing electron scattering, and the establishment of a synergistic "scattering-trapping-enhancement" protective network via the sandwich structure. These work presents a design strategy for developing PI-based composite film with enhanced electron irradiation resistance.