Achieving enhanced thermal conductivity and low dielectric constants using double-oriented fluorinated graphene skeleton in silicone gel composites

Abstract

The dielectric properties and thermal conductivity of composites are often contradictory. To improve the thermal conductivity, the filler content needs to be increased, which often contributes to the high dielectric constant of the material. Inspired by the layout of community buildings, in this study, silicone gel/double-oriented fluorinated graphene skeleton composites were prepared, which solved the difficulty in assembling fluorinated graphene in situ into a three-dimensional continuous network structure. This greatly improved the thermal conductivity and reduced the dielectric constant of the silicone gel while maintaining a low filler content and the insulating properties. In addition, based on the reconstruction of a real three-dimensional body, the mechanism by which the skeleton improved the material performance was analyzed using finite element simulation. The vertical and horizontal thermal conductivity of the silicone gel/double-oriented fluorinated graphene skeleton composites reached 3.34 W/(m·K) and 2.65 W/(m·K), respectively, and the dielectric constant dropped to 80 % of that of pure silicone gel. This provided a new way to synergistically improve the dielectric properties and thermal conductivity of insulating materials, and has great application potential as a thermal interface material in next-generation electronic devices.