Architecture-driven synergistic enhancement of thermal conductivity and electrical insulation in epoxy composites via core-shell Al@Al2O3–AlN microcapsules

Overcoming the trade-off between thermal conductivity and electrical insulation is critical for the development of polymer-based thermal interface materials (TIMs) for advanced electronic packaging. Herein, a multifunctional thermal management strategy based on metal microcapsules is proposed for the first time, which is realized through the fabrication of core-shell Al@Al 2 O 3 -AlN microcapsules and epoxy composites. The multifunctional composites are systematically characterized through experimental and numerical simulation methods. Experimental results show that the multifunctional composite exhibits a thermal conductivity of 7.49 W·m -1 ·K -1 , more than 36 times that of neat epoxy, together with a low thermal resistance of 0.000267 m 2 ·K/W, a high volume resistivity of 3.2×10 12 Ω·cm, and a dielectric loss factor below 0.04 at high frequencies. This superior combination of properties is attributed to the construction of efficient thermally conductive pathways by the Al@Al 2 O 3 -AlN microcapsules and the effective suppression of electron transport by the insulating Al 2 O 3 -AlN shell. Numerical simulations further elucidate the thermal and electrical transport behavior and underlying mechanisms. This work offers a new paradigm for developing electrically insulating polymer-based thermal interface materials with high thermal conductivity for advanced electronic packaging applications.