Promoting the thermal transport via understanding the intrinsic relation between thermal conductivity and interfacial contact probability in the polymeric composites with hybrid fillers

Polymeric composites with thermally conductive hybrid fillers are significant in the electronics and thermal dissipation, where thermal transport along with multifunctionality is required to meet the application needs. Introduction of hybrid fillers would induce multiple interface scattering and rational design on the filler contact should be the critical criteria, while there is insufficient principle. To promote the thermal transport capability, in this paper, a contact probability model has been established to quantitatively analyze the thermal conductivity and contact probability in the silicone rubber composites with hybrid fillers (including various aluminium oxides and silicon carbide whisker). The results from experiment and simulation suggest that three critical parameters, i.e. volume fraction, filler shape and filler size, are the essential factors of hybrid fillers on impacting the thermal conductivity of composites. With understanding the contact types of hybrid filler, the optimized thermal conductivity has been obtained in the composites with aluminium oxides and silicon carbide whisker fillers. The model and analysis here have provided new contact mechanism for understanding the thermal transport in composites, which could be extended to rationally design and fabricate other types of polymeric composites with hybrid fillers.