Anisotropic polymer composites for thermal management and EMI shielding: A strategy using graphene foam and liquid metal binary fillers
摘要
The integration of efficient thermal conduction and electromagnetic interference (EMI) shielding functions into flexible polymer-based materials is crucial for enhancing the stability and performance of modern miniaturized electronics. Herein, we prepared polymer composites filled with aligned compressed graphene foam (c-GF) and dispersed liquid metal (LM) droplets, investigating the effects of different fillers and their structural orientation on the thermal conductivity (TC), electrical conductivity, and EMI shielding properties of the composites. Through a simple macro-preparation method, pad-like polymer composites with distinct thermal/electrical conduction pathways were obtained, enabling control over anisotropic properties. When the c-GF loading is approximately 4 wt% and the LM loading is about 20 wt%, the polymer composite with vertically oriented c-GF sheets achieves a through-plane TC of 4.96 W m−1 K−1 and an EMI shielding effectiveness (EMI SE) of 28.4 dB. In contrast, the composite incorporating in-plane oriented c-GF sheets exhibits a significantly lower through-plane TC of only 0.41 W m−1 K−1 but a markedly higher EMI SE value of 46.8 dB. The combination of c-GF and LM facilitates the design of polymer-based composites with flexibly tunable thermal and electrical properties, meeting the application demands of flexible multi-functional composites in electronic packaging, thermal management, and EMI shielding.
Graphical abstract