Polyhedral Oligosilsesquioxane-Modified Alumina/Aluminum Nitride/Silicone Rubber Composites to Enhance Dielectric Properties and Thermal Conductivity

Interfacial thermal resistance is the primary impediment to heat flow in materials and devices. This thermal boundary conductance across solid interfaces can affect high-powered thermal conductive materials. In this work, we propose an approach to decreasing the interfacial thermal resistance by improving both the contact area and the interconnection between fillers. Polyhedral oligosilsesquioxane (POSS)-functionalized alumina/aluminum nitride was used as a filler to prepare an ideal dielectric and thermally conductive silicone rubber composite. When the added amount of POSS is 0.3 wt.%, thermal conductivity will increase by 21%. It will also have excellent dielectric properties, with a dielectric constant of 2.2 and a dielectric loss of 0.002. The advantages of the composite we designed are due to the effective surface modification of POSS molecules, the principle of multi-size particle adaptation, and the excellent intrinsic properties of thermally conductive particles. Graphical Abstract Schematic of surface modification of the fillers