High thermal conductivity, low dielectric constant and good processability of epoxy composites achieved by boron nitride/hollow glass microsphere heterostructured particles

Heterogeneous structured BN@HGM was constructed via electrostatic self-assembly. • The EP-based composites showed high thermal conductivity. • Suppressed dielectric polarization was achieved. • Viscosity of the composites was maintained at relatively low level. The growing demands of high-power-density and high-frequency electronics require epoxy (EP) composites that achieve a simultaneous balance of high thermal conductivity, low dielectric response, and low viscosity. This study reports a heterostructured particle design, where hollow glass microspheres (HGM) are coated with boron nitride (BN) nanosheets through electrostatic self-assembly, achieving functional partitioning. The BN shell forms continuous thermal pathways, the hollow HGM core introduces air to reduce dielectric polarization, and the confinement of BN nanosheets on spherical HGM suppresses viscosity rise of composites. As a result, the 30 B N@M-HGM/EP achieves an optimal balance among performances, with a thermal conductivity (κ) of 2.4 W/m·K, a dielectric constant ( D k ) of 3.7 at 1 MHz, and a viscosity of 12.43 Pa s, outperforming the conventional composite prepared through physical compounding. Encapsulation tests of electronic components further confirm the good thermal management of the composites, reducing the maximum operating temperature by 27.1 °C. These results demonstrate that the heterostructured engineering of composite particles offers an effective and scalable approach for the simultaneous optimization of thermal, dielectric, and rheological properties in epoxy-based electronic packaging materials. Download: Download high-res image (389KB) Download: Download full-size image