Synchronously improved thermal conductivity and dielectric constant for epoxy composites by introducing functionalized silicon carbide nanoparticles and boron nitride microspheres.

Polymer-based dielectrics with high thermal conductivity and superb dielectric properties hold great promising for advanced electronic packaging and thermal management application. However, integrating these properties into a single material remains challenging due to their mutually exclusive physical connotations. Here, an ideal dielectric thermally conductive epoxy composite is successfully prepared by incorporating multiscale hybrid fillers of boron nitride microsphere (BNMS) and silicon dioxide coated silicon carbide nanoparticles (SiC@SiO). In the resultant composites, the microscale BNMS serve as the principal building blocks to establish the thermally conductive network, while the nanoscale SiC@SiO as bridges to optimize the heat transfer and suppress the interfacial phonon scattering. In addition, the special core-shell nanoarchitecture of SiC@SiO can significantly impede the leakage current and generate a great deal of minicapacitors in the composites. Consequently, favorable thermal conductivity (0.76 W/mK) and dielectric constant (∼8.19) are simultaneously achieved in the BNMS/SiC@SiO/Epoxy composites without compromising the dielectric loss (∼0.022). The strategy described in this study provides important insights into the design of high-performance dielectric composites by capitalizing on the merits of different particles.