ScholarWorks@성균관대학교

초록

The rapid miniaturization and escalating integration of high-performance electronic systems necessitate the development of flexible, lightweight materials with superior electromagnetic interference (EMI) shielding and thermal conductivity (TC). However, conventional conductive shields often lead to secondary pollution, underscoring the need for absorption-dominant materials that effectively reduce electromagnetic reflections. Herein, flexible sandwich-structured composite films composed of bimetallic copper‑zinc-1,3,5-benzenetricarboxylate (CuZn-BTC) MOF-derived CuZn@C and graphene nanoplatelets (GnP) are fabricated via a scalable layer-by-layer vacuum filtration process using cellulose nanofibers (CNFs) as a matrix. The tritopic BTC ligand-derived carbon affords more metal-ligand coordination than monotopic and bitopic ligands and an enhanced conductive carbon network upon carbonization, thereby enhancing EMI shielding and thermal conductivity (TC). The resulting flexible CuZn@C/GnP/CuZn@C-CNF (MGM) sandwich architecture exhibits absorption-dominant EMI shielding with an effectiveness of 55 dB, in the X-band (8–12 GHz) at an ultrathin thickness of only 80 μm. The enhanced EMI shielding performance is attributed to interfacial polarization and dielectric loss in the CuZn@C-CNF outer layers, resulting in 80% improvement over homogeneous GnP-CNF composites. Moreover, the synergistic integration of highly conductive interconnected GnP networks and thermally conductive Cu and Zn nodes embedded in crystalline carbon, along with strong interfacial interactions within the MGM composite film, yields an exceptionally high in-plane TC of 47 W·m−1·K−1. In addition, the composite films demonstrate significantly improved mechanical performance, including a tensile strength of 247 MPa, a high Young's modulus of 18.65 GPa, enhanced toughness of 1.92 MJ.m−3, and excellent flexibility. This work highlights the synergistic integration of MOF-derived carbon and graphene fillers within a sandwich structure to develop lightweight, flexible materials for advanced EMI absorption and thermal management applications.

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