Hexagonal boron nitride (hBN) is a structural analog of graphene, made out of a honeycomb-like lattice of boron and nitrogen atoms. It has unique mechanical, thermal, and optical properties that make it useful for a variety of applications. To produce materials with hBN on an industrial scale, an important step is to be able to obtain stable dispersions of exfoliated hBN nanosheets, preferably in a nontoxic and inexpensive manner. In this work, we studied the use of surfactants to disperse and exfoliate hBN in aqueous solutions. By studying dispersions in nine surfactants with different characteristics plus water, we were able to compare their dispersion yield, quality of exfoliation, and stability over time. Results show that when using a low centrifugal force (100g) to prepare the dispersions, large molecular weight nonionic surfactants disperse the most material, however, the quality and stability of the dispersions were poor. When using a stronger centrifugal force (8000g), all surfactants produce similarly smaller dispersion yields and had significantly higher quality. Dispersions in ionic surfactants, in particular, contained more exfoliated nanosheets, about 1-2 layer thick, and remain stable over longer periods of time. To demonstrate the scalability and effectiveness of the dispersions to produce macroscopic materials, a transparent film was produced from a dispersion made with sodium dodecyl sulfate. The film can be deposited on glass and it can be potentially used as an antibacterial or thermally resistant coating.

Dispersion and exfoliation of hexagonal boron nitride nanosheets using surfactants

ACS Spring Meeting 2021

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