Graphite/Liquid Metal/Thermoplastic Polyurethane Composite Film Based on Interfacial Architectural Engineering for Synergistic Electromagnetic Interference Shielding and Thermal Management

The flourishing electronics industry has raised great challenges to deal with the mounting electromagnetic interference and thermal management. By constructing an efficient oriented material structure, excellent electrical conductivity and thermal conductivity could be achieved along the oriented direction. However, there is always a difference in thermal conduction ability between in-plane direction and through-plane direction. The through-plane conduction for electrons and phonons is hindered due to the lack of interlamellar interactions between the oriented fillers. Herein, graphite/liquid metal/thermoplastic polyurethane composite (G/LM/TPU) film was fabricated by simple blade coating and rolling, forming parallel-oriented graphite sheets and intercalated liquid metal droplets. The blade coating process enabled the parallel orientation of graphite sheets along the coating direction. While the rolling process applied certain press to destroy the oxide layer of LM droplets inside the composites, enhancing the orientation and filler network connection. Leaked LM droplets have constructed perpendicular interactions along the through-plane direction, which has led to further improvement of the electrical conductivity (1.91 × 10 ⁴ S•m ⁻¹ ), thermal conductivity (1.66 W•m ⁻¹ •K ⁻¹ ), and EMI shielding effectiveness (60.1 dB). The through-plane thermal conductivity and EMI shielding effectiveness were increased by 143% and 146%, respectively. This work provides a promising strategy to enhance EMI shielding and thermal conductivity of functional composites by introducing oriented and bridge structure.