Magnetic field-assisted alignment of boron nitride nanosheets in poly(vinyl alcohol) composites with enhanced in-plane thermal conductivity

With the advent of the 5G era, various thermal conductivity nanocomposites are being investigated to solve the heat accumulation on the surface of electronic devices. In this study, magnetic nanofiller ferroferric oxide-polydopamine-boron nitride nanosheets (Fe-PDA-BNNSs) are fabricated by mussel-inspired and coprecipitation methods with polydopamine (PDA) and ferroferric oxide (Fe 3 O 4 ). The aligned Fe-PDA-BNNSs/poly(vinyl alcohol) (PVA) composites with higher in-plane thermal conductivity and decent mechanical properties are prepared by applying a horizontal magnetic field. The in-plane thermal conductivity of the aligned composite at 30 wt% filler loading reaches 5.237 W/(m·K), which is 1.1 times and 20.5 times that of the unaligned composites and neat PVA. Moreover, the aligned composite maintains mechanical strength and obtains commendable thermal stability and heat dissipation capability, which can be applied to the thermal management of flexible electronic devices.