Thermally Conductive, Electrically Insulating Epoxy Pads with Three-Dimensional Polydopamine-Modified and Silver Nanoparticle-Functionalized Hexagonal Boron Nitride Networks

Electronic components are susceptible to failure due to overheating during operation. Consequently, there is a growing demand for thermally conductive pads (TCPs) that exhibit high thermal conductivity (TC) and electrical insulation properties in electronic packaging. In this study, we synthesized hBN* particles by modifying hexagonal boron nitride (hBN) with polydopamine (PDA). Subsequently, a hybrid thermal conduction filler of hBN*@Ag was prepared by functionalizing silver nanoparticles (AgNPs) on the hBN* surface. Using a hard-template method, a three-dimensional thermally conductive network of hBN*@Ag (3D-hBN*@Ag) is constructed, and epoxy (EP) composites with 3D-hBN*@Ag (3D-hBN*@Ag/EP) are fabricated through the vacuum impregnation method. The results indicate that PDA enhances the interfacial compatibility of hBN-EP and reduces the filler–matrix interfacial thermal resistance (ITR f–m ). However, the new interface brought by PDA will increase the filler–filler interfacial thermal resistance (ITR f–f ), resulting in no significant improvement of the TC of 3D-hBN*/EP compared to 3D-hBN/EP. The AgNPs sandwiched between hBN layers are essential for enhancing the TCs of 3D-hBN*@Ag/EP composites, which contribute to an increased number of contact points between hBN layers, thereby reducing the ITR f–f . Moreover, a small amount of functionalized AgNPs on hBN will not change the electrical insulation characteristics of the composites. The resulting lightweight 3D-hBN*@Ag 6.0/EP possesses a high TC of 1.381 W m –1 K –1 at 26 wt % filler content. This study presents a strategy for improving the TC limit of composites with 3D filler networks, albeit at the expense of some electrical insulation properties.