Hexagonal Boron Nitride Nanosheets Exfoliated Using the New Approach

A new mechanical process for controlling the exfoliation of hexagonal boron nitride nanosheets (h-BNNS) known as the “water-icing triggered exfoliation process,” has been described by Chinese researchers.

The Boron nitride nanosheet is a 2D crystalline form of the hexagonal boron nitride, with just a few atomic layers thick, they are similar in their geometry to graphene but differ in their chemical and electronic properties. The honeycomb-like structure of h-BNNSs gives them excellent thermal conductivity, good oxidation resistance, remarkable mechanical strength, a low dielectric constant, excellent lubricity, excellent biocompatibility, and excellent optical properties. And these properties make it very useful for applications like high-performance electronic devices, dielectric substrates, thermal management, lubrication, sensors, catalysts, and sorbents. The development of simple, controllable, and scalable methods to produce high-quality h-BNNSs is therefore imperative.

In the newly published study, Prof. ZHANG Junyan’s group by using efficient reduction of h-BNNS interlayer interaction by rapid volume expansion of water in icing was able to propose a scalable and controllable approach to exfoliate high-quality h-BNNSs from h-BN flakes.

They adjusted a few parameters for successfully achieving this exfoliation process for large quantities of different high-quality h-BNNSs. Their method is environmentally friendly as they exfoliate h-BNNSs with controllable thickness by a rapid water freezing and subsequent ultrasonication process. Its application includes, but is not limited to, polymer additives, thermally conductive fillers, and flame retardants.