Iron Oxide/Magnesium Oxide/Graphene Oxide/Cellulose Composites with Superior Thermal Conductivity, EMI Shielding, and Electrical Insulation Synthesis Using Polydopamine Linker

Rapid advances in electronic devices have accelerated the requirements for effective heat management. Concurrently, the proliferation of wireless communication has intensified concerns related to electromagnetic interference (EMI) shielding. Excessive heat and EMI pose significant threats to the functionality of electronic devices and human health. To mitigate these risks, materials that offer exceptional thermal conductivity and high EMI shielding effectiveness (EMI SE) are required. However, studies on composite materials that provide both electrical insulation and EMI shielding are limited. Herein, we systematically functionalized graphene oxide (GO) sheets with polydopamine (PDG). We also surface-treated iron oxide (IO) and magnesium oxide (MO) nanoparticles with polydopamine. IO and MO nanoparticles were covalently linked to GO sheets with polydopamine (PDG/IO/MO), ensuring even dispersion of IO and MO nanoparticles across the PDG sheets. This unique PDG/IO/MO hybrid filler exhibited strong affinity for integration with a polydopamine-treated cellulose matrix, creating double heat transfer pathways due to the strategic positioning of IO and MO fillers on the PDG sheets. By chemically bonding the fillers and the matrix, the composites' performance was further enhanced. Consequently, the developed cellulose/PDG/IO/MO composites exhibited excellent electrical insulation (exceeding 109 Ω·cm), EMI SE (65.29 dB), through-plane thermal conductivity (5.83 W/m·K), and tensile strength (155.49 MPa). We posit that, due to their electrical insulation and EMI shielding properties, these composites hold significant potential for application as electronic packaging materials.