High strength, stable and self-healing copolyimide for defects induced by mechanical and electrical damages

Abstract

Self-healing of damage is a common phenomenon in organisms but is hardly ever encountered in rigid polymer materials. For next-generation electricals and electronics, it is crucial to accurately mimic organisms to detect and heal mechanical/electrical damage. Herein, disulfide bond exchange is designed to introduce the self-healing ability in a copolymerized polyimide (copolyimide). A copolyimide insulation film with two diamine monomers is successfully prepared, which also possesses good self-healing ability after being mechanical/electrical damaged. Furthermore, the self-healing copolyimide film still maintains its good Young's modulus (E) >4 GPa, high thermal stability with glass transition temperature (T_g) >190 °C, and excellent insulation property with breakdown strength (E_b) >300 kV mm⁻¹. The combination of the simple copolymerization and unique self-healing ability is suitable for high T_g polyimide to make this an ideal method for insulation field.