GMP/Al₂O₃/ZnO/PDMS thermal interface materials with anisotropic thermal conductivity and electrical insulation ability obtained by 3D-printing method

Due to the continuous increase in power density and power consumption, thermal management has become a crucial issue in electronic devices like integrated circuits. Polymer-based thermal conductive composites possess excellent thermal and mechanical properties, making them ideal materials for thermal management in the modern microelectronic industry. In this work, we present a combination of filler hybridization strategy and 3D-printing technology to synergistically enhance the thermal conductivity of graphite microplatelets (GMP)/alumina (Al₂O₃)/zinc oxide (ZnO)/polydimethylsiloxane (PDMS) composite (o-GAZP). When the content of GMP reaches 4.5 vol%, the 3D-printed composite material exhibits a directional thermal conductivity of up to 4.51 W m⁻¹ K⁻¹. This value is significantly higher than the thermal conductivity of a randomly mixed GMP/Al₂O₃/ZnO/PDMS composite (1.98 W m⁻¹ K⁻¹). The remarkable thermal conductivity can be attributed to the anisotropic structural design, which benefits from the orientation of GMP and the creation of a multi-scale dense structure through filler compounding. Additionally, the presence of Al₂O₃ and ZnO effectively separates the GMP particles, preventing the formation of electron transfer pathways and improving the electrical insulation performance of the composites. Furthermore, the impact of the anisotropic structural design on the thermal conductivity of the composites was verified through finite element simulation. This study demonstrates that constructing efficient thermally conductive and electrically insulating pathways by densely packing highly oriented two-dimensional anisotropic graphite-based fillers with uniformly dispersed thermally conductive and electrically insulating fillers is a simple and effective method to enhance the composites' thermal conductivity, electrical resistivity, and mechanical properties simultaneously. These findings hold great potential for various scalable thermal-related applications. By implementing this approach, composites can exhibit excellent thermal conductivity, high electrical resistivity, and superior mechanical performance.