Liquid-Phase Exfoliation of Hexagonal Boron Nitride into Boron Nitride Nanosheets in Common Organic Solvents with Hyperbranched Polyethylene as Stabilizer

Abstract

Large-scale production of boron nitride nanosheets (BNNSs) is of significant importance for their various applications. Herein, a facile strategy is well demonstrated for BNNS fabrication via liquid-phase exfoliation of bulk hexagonal boron nitride (h-BN) in common organic solvents with hyperbranched polyethylene (HBPE) as stabilizer. Synthesized from commercially abundant ethylene stock via a simple process, the HBPE is found to effectively promote h-BN exfoliation both in tetrahydrofuran and chloroform under sonication, to render stable dispersions of high-quality monolayer or few-layer BNNSs with adjustable concentrations. This has been confirmed to originate from the noncovalent CH–π interactions between the HBPE and BNNS surface, which results in irreversible HBPE adsorption on the latter to effectively prevent their reaggregation. The resultant HBPE-functionalized BNNSs are highly dispersible in chloroform or N,N-dimethylformamide at a concentration as high as 10.0 mg mL−1, and can be successfully used as nanofiller for a fluorinated copolymer.