Facile fabrication of three-dimensional thermal conductive composites with synergistic effect of multidimensional fillers

Thermal conductive polymer composites are promising in the application of rapidly developing modern technology. Here, a facile method to fabricate three-dimensional thermal conductive composites with multidimensional fillers was reported. One-dimensional AgNW were used to bridge the randomly dispersing two-dimensional BNNS together in poly(dimethylsiloxane) (PDMS) to form thermal conductive networks. The through-plane thermal conductivity (0.64 W m⁻¹ K⁻¹) of composite 2wt%AgNW/20wt%BNNS/PDMS was 237% higher than that of matrix PDMS (0.19 W m⁻¹ K⁻¹), while the composites still maintained good electrically insulating. A series of theoretical models were used to describe the thermal conductivity as a function of BNNS contents with or without the presence of AgNW. The synergistic effect between BNNS and AgNW was verified from the calculation of interfacial thermal resistance, which decreases from 1.06 × 10^–6 m² K W⁻¹ for system without AgNW to 6.14 × 10^–9 m² K W⁻¹ for system with 2 wt% AgNW. This synergistic strategy via multidimensional fillers supported the methodological possibility of returning to simplicity from various template approaches which were limited in shape and size. It was expected to extend the understanding of available theory and predict the potential formation of 3D thermal conductive networks in other systems with multidimensional fillers.