A densified conductive network of CNT-bridged vertical ZnO arrays for enhanced EMI shielding, mechanical, and thermal properties of carbon fiber/polymer composites

In response to the growing demands of advanced electronics with integrated electromagnetic interference (EMI) shielding and efficient thermal management, this study develops a multifunctional carbon fiber reinforced polymer composite (CFRP) through a biomimetic hierarchical interface design. A multi-level interfacial engineering approach is employed: first, polydopamine activation improves interfacial adhesion; second, vertically-aligned ZnO nanorod (NRs) arrays are grown in situ to provide mechanical interlocking, dielectric loss, and radial heat conduction pathways; finally, a sheet-like carbon nanotube (CNT) network bridges adjacent fibers, forming a densified, continuous conductive framework. This organic-inorganic, “line-plane” coupled architecture results in remarkable multifunctional enhancement: the composite achieves an EMI shielding effectiveness of 30.8 dB in the X-band, a through-plane thermal conductivity of 0.71 W m −1 K −1 , and significant mechanical improvements—interlaminar shear strength and flexural strength increased by 57.4% and 84.3%, respectively. Efficient Joule heating and photothermal response are also demonstrated. This work presents a scalable hierarchical interface strategy that synergistically integrates structural, thermal, and electromagnetic functions, offering a viable design pathway for next-generation structural materials in EMI-sensitive applications.