Concurrent Realization of Robust Mechanical Strength and Rapid Self-Healing in Polyimides via a Dynamic Bonding Approach

Polyimides (PIs) are used in cutting-edge engineering fields due to their high mechanical strength, excellent electrical insulation, and low friction coefficient, attributed to their rigid benzene ring structures. However, under prolonged service in harsh environments, PI components are prone to mechanical damage, which substantially increases the risk of operational failure and maintenance costs. Thus, developing self-healing PI materials has become crucial for enhancing operational reliability and extending service life. Nevertheless, achieving a material that simultaneously exhibits high mechanical strength, high healing efficiency, and rapid healing capability remains a formidable challenge. In this work, the formylphenylboronic acid is introduced as a single monomer to concurrently incorporate dynamic imine bonds (-C═N-) and reversible boroxine structures (-B 3 O 3 -) into the PI backbone, achieving a “two birds with one stone” molecular design. This strategy endows the resultant PI with excellent mechanical properties (a tensile strength of 87.03 MPa and a break elongation of 21.41%) and a breakthrough self-healing property, enabling repair efficiency of 99.92% and damage repair in just 30 s. Notably, it resolves the critical bottleneck in the field─the typical trade-off between strength/toughness and rapid/healing efficiency─with the achieved efficiency and speed being the highest values reported to date. Furthermore, inspired by the perspiration and healing mechanisms of human skin, a heterogeneous bilayer architecture is constructed to further enhance the healing material’s resistance to extreme mechanical damage such as severe abrasion under heavy-load conditions. This work not only opens up a new avenue for designing integrated materials that combine high strength, thermal stability, and ultrafast self-healing capacity, but also provides a practical strategy for prolonging the service life of PIs in extreme environments while mitigating risks associated with unexpected mechanical failures.