Dynamic Sustainable Polyimide Film Combining Hardness with Softness via a “Mimosa‐Like” Bionic Strategy

• Published in: Advanced materials (Weinheim) 2023-01, Vol.35 (2), p.e2207451-n/a
• Main Authors: Wan, Baoquan, Yang, Xing, Dong, Xiaodi, Zheng, Ming‐Sheng, Zhao, Quanliang, Zhang, Hongkuan, Chen, George, Zha, Jun‐Wei
• Format: Article
• Language: English
• Subjects: Bionics; Carbon fibers; Composite materials; Crosslinking; Design; Electric power systems; Electricity; Electronic devices; Electronics; Field strength; Hardness; High temperature; Mimosa; Molecular structure; polyimide; Polyimide resins; Recyclability; Response time; self‐healable materials; Softness; Sustainable development
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202207451

Dielectric polyimides (PIs) are ubiquitous as insulation in electrical power systems and electronic devices. Generally, dynamic polyimide is required to solve irreversible failure processes of electrical or mechanical damage, for example, under high temperature, pressure, and field strength. The challenge lies in the design of the molecular structure of rigid polyimide to achieve dynamic reversibility. Herein, a low‐molecular‐weight polyimide gene unit is designed to crosslink with polyimide ligase to prepare the smart film. Interestingly, due to the variability of gene unit and ligase combinations, the polyimide films combining hardness with softness are designed into three forms via a “Mimosa‐like” bionic strategy to adapt to different application scenarios. Meanwhile, the films have good degradation efficiency, excellent recyclability, and can be self‐healable, which makes them reuse. Clearly, the films can be used in the preparation of ultrafast sensors with a response time ≈0.15 s and the application of corona‐resistant films with 100% recovery. Furthermore, the construction of polyimide and carbon‐fiber‐reinforced composites (CFRCs) has been verified to apply to the worse environment. Nicely, the composites have the property of multiple cycles and the non‐destructive recycle rate of carbon fiber (CF) is as high as 100%. The design idea of preparing high‐strength dynamic polyimide by crosslinking simple polyimide gene unit with ligase could provide a good foundation and a clear case for the sustainable development of electrical and electronic polyimides, from the perspective of Mimosa bionics. A dynamic polyimide (PI) film, which can transform among three molecular structures, is designed by imitating the behavior of the Mimosa plant. The PI film is a super‐corona‐resistant film, a matrix of high‐sensitivity humidity sensor and carbon‐fiber‐reinforced composites due to its excellent capabilities of degradation, self‐healable ability, and recyclability.