Reactive Molecular Dynamics of Atomic Oxygen Bombardment on Polyimide under Electric Field

Polyimide (PI) possesses excellent insulating properties and is widely used in spacecraft electrical transmission devices and equipment. To deeply investigate the degradation mechanism of polyimide solid insulating materials under the bombardment of atomic oxygen (AO) in an electric field, the ReaxFF (reactive force field) reactive molecular dynamics method was employed. The erosion process of Kapton-type polyimide under the influence of an electric field was computationally simulated. Various electric field strengths were applied to the polyimide simulation system, ranging from 0.6, 0.8, 1.0, 1.2, to 1.4 V/nm. The results indicate that under a weaker electric field, the bombardment kinetic energy of AO is reduced, resulting in little change in the overall mass loss. However, a stronger electric field exacerbates the cleavage of polyimide, and the normalized mass loss increases with the simulation time. Material loss induced by atomic oxygen bombardment in an electric field environment is a primary cause of insulation failure in aerospace equipment.