Durable and Self‐Healable Glassy Composites for Reliable Electromagnetic Interference Shielding

ABSTRACT Although effective electromagnetic interference (EMI) shielding materials have been developed for next‐generation electronics, conventional glassy thermosetting composites usually suffer from irreparable microcracking and gradual performance loss, thus severely limiting their long‐term durability and stability. Herein, we report a self‐healable glassy thermosetting composite that integrates high mechanical strength with efficient EMI shielding functionality. Graphene (GE) was ultrasonically dispersed into a dynamically reconfigurable hyperbranched polymer (HBP) network, enabling rapid restoration of both mechanical integrity and electrical functionality. At 20°C, the composite achieves 98.5% mechanical healing efficiency within 60 min and recovers to 95.5% of its original EMI shielding effectiveness after 48 h of healing. Meanwhile, excellent EMI shielding durability is maintained, with 96.9% retention of the initial shielding effectiveness, even after repeated mechanical deformation. Spectroscopic analyses and interfacial diffusion study revealed that dynamic exchange between disulfide bonds and hydrogen‐bond interactions cooperatively contributed to the observed self‐healing performance. This work provides an effective materials design strategy for high‐strength, repairable glassy thermosetting composites, expanding their potential in durable EMI shielding and next‐generation electronic systems.