Transparent Silicone Calcium Fluoride Nanocomposite with Improved Thermal Conductivity

Heat dissipation is an important issue in many electronic devices and therefore materials showing high thermal conductivity are required for their construction and packaging. The intrinsically low thermal conductivity of polymeric materials can be improved when employing (nano-) composites; however, the required high filler content then renders these materials opaque. This paper reports on a composite material that combines high transparency and improved thermal conductivity by using calcium fluoride (CaF2) particles in a silicone elastomer. The refractive index of the silicone matrix is matched to the filler material, light scattering is prevented, and transparent composites with enhanced thermal conductivity at modest filler content (starting at 0.2 volume fraction) are obtained.