Enhancement in thermal conductivity of polymer composites through vertically parallel multilayered distribution of microdiamonds

Abstract

We propose a strategy to realize a vertically parallel multilayered distribution of microdiamonds in a polymeric matrix by pre-constructing layers with abundantly stacked microdiamonds. Silicone-based composites with this microdiamond arrangement exhibit interesting material properties in the through-plane direction: significant increments in thermal conductivity (335% that of composites with a random structure at a similar low loading of 24.7 vol%), and excellent dielectric properties as thermal interface materials for applications such as radars. Novel numerical models focused on this design of microdiamond arrangement are proposed to further understand mechanism of thermal conductivity increment and are found to match thermal conductivity and tendency of composites with this type of microdiamond distribution. It is revealed that adjusting microstructures in pre-constructed microdiamond layers is regarded as an effective strategy to improve further thermal conductivity of composites.