Boron nitride nanosheets from high shear exfoliation for high-performance thermal conductivity films

Boron nitride nanosheets (BNNSs) with intrinsically ultra-high thermal conductivity have attracted more and more attention and various methods have been proposed to prepare BNNSs-based thermally conductive adhesives. In this work, a liquid phase shear exfoliation process was proposed to prepare BNNSs. BNNSs can be directly prepared by exfoliating h-BN particles dispersed in isopropanol at a controlled rotational speed range of 16,000–22,000 rpm and the maximum yield of BNNSs is up to 32.1%. After the BNNSs were modified with polydopamine (M-BNNSs), the dispersion performance of BNNSs in water was significantly improved. BNNSs were incorporated into a cellulose nanofiber-based adhesive, and the highly thermally conductive films were prepared by a flow-delay process. A tested in-plane thermal conductivity of up to 23.23 W·m−1·K−1 and excellent mechanical properties are demonstrated and thermal infrared images provide a more visual representation of the high thermal conductivity and heat dissipation properties of the film, indicating the promising application of the film in the field of thermal conductivity.