Liquid metal bridging boron nitride/bacterial cellulose composite films with excellent thermal and mechanical performance

With the continuous miniaturization and highly integrated development of modern electronics, thermal management materials with high thermal conductivity, good electrical insulating and flexibility are highly desired for the effective heat dissipation to maintain the reliable operations of electronic devices. However, enhancing thermal conductivity generally causes the deterioration of their mechanical properties and electrical insulation. Herein, combining the deformability of Galinstan-based liquid metal (LM) and good film-forming property of bacterial cellulose (BC), a series of thin and flexible boron nitride-based composite (BC/BNNS-LM) films was prepared via a facile vacuum-assisted filtration route. Benefiting from the directional arrangement of BNNS nanosheets, as well as gap-filling and bridging effects of deformable LM droplets, the resultant BC/BNNS-LM ternary nanocomposite film not only presents a high in-plane thermal conductivity of 66.1 W/m center dot K but also achieves excellent mechanical strength, flexibility and good dielectric property. These desirable properties confirm that the fabricated nanocomposite films have significant potential for effective heat dissipation in high- power-density electronics.