Large-scale production of boron nitride nanosheets for flexible thermal interface materials with highly thermally conductive and low dielectric constant

As the operating power of electronic devices used in 5G technology continues to rapidly progress, demand is increasing for thermal conductive composites with exceptional dielectric insulating properties. Boron nitride nanosheets (BNNS)-based composites have garnered significant attention owing to the extraordinary inherent thermal conductivity and excellent dielectric insulation of BNNS. However, a bottleneck of mass exfoliation high-quality BNNS severely delays the advancement of BNNS-based composites. Herein, the large-scale production BNNS are attained through novel exfoliation method by rationally introducing vigorous ultrasonication treatment with an ultra-high power up to 1200 W. By acquiring approximately 32 g of high-quality BNNS in 5 cycles, the yield can be increased to around 40 %. The multilevel casting strategy prepared polydimethylsiloxane PDMS/BNNS composite exhibits a significantly enhanced κ⊥ of achieve to 3.82 W m−1 K−1 at 50 wt % of BNNS loading along with a low interfacial thermal resistance of 38 K mm2 W−1 and dielectric constant below 3. This finding provides a promising path for the massively producing high-quality BNNS and thermal interface materials to enhance thermal transport from electronics to heat sink.