Holocellulose nanofibrils assisted exfoliation of boron nitride nanosheets for thermal management nanocomposite films

High-quality boron nitride nanosheets (BNNSs) were exfoliated via eco-friendly holocellulose nanofibrils (HCNFs) assisted ultrasound treatment in water. The resultant H-BNNSs possessed high yields (23.4%), few surface defects, a high aspect ratio (~134), and excellent dispersibility in water (Zeta potential, -53.5 mV). Furthermore, H-BNNSs were functionalized by liquid metal (Gallium, Ga) dominated interface engineering and assembled with cellulose fibers into Ga@H-BNNSs filled nanocomposite films. Owing to the well-designed interface engineering, the obtained nanocomposite films exhibited outstanding integrated performance, especially excellent in-plane thermal conductivity (11.78 W m-1 K-1), and had great potential in the thermal management of flexible electronics.