ZnO@C/PEDOT ‐Modified Carbon Fibers for Synergistic Enhancement of Mechanical and Electromagnetic Interference Shielding Properties of Carbon Fiber Composites

ABSTRACT The increasing electromagnetic radiation from electronic devices has created an urgent demand for structural composites that simultaneously exhibit high mechanical performance and effective electromagnetic interference (EMI) shielding capability. Herein, a multiscale interfacial modification strategy for carbon fiber (CF) composites is proposed to achieve synergistic enhancement of load transfer efficiency and EMI shielding performance. Zn‐based metal–organic framework (Zn‐MOF) is first in situ grown on the CF surface via a polydopamine (PDA) interlayer, followed by a two‐step calcination process to generate a tightly bonded ZnO/C hybrid coating. Subsequently, a conductive PEDOT:PSS (PP) layer is deposited to construct a hierarchical conductive network. Owing to the optimized multiscale interfacial architecture, the resulting CF‐PDA‐ZnO‐PP composites exhibit significant improvements in mechanical properties, with the interlaminar shear strength, flexural strength, and flexural modulus increased by 44%, 41%, and 87%, respectively, compared with untreated CF composites. Meanwhile, the composite achieves a total shielding effectiveness (SE _T ) of 44 dB, indicating excellent EMI shielding capability. This work provides a feasible and scalable approach for the design of next‐generation structural composites with high load‐bearing capacity and EMI shielding functionality, showing strong potential for applications in aerospace, transportation, and high‐end electronic equipment.