Tunable Alkylation of White Graphene (Hexagonal Boron Nitride) Using Reductive Conditions

Hexagonal boron nitride (h-BN), also known as white graphene, presents an unparalleled combination of properties, including superior mechanical strength, good thermal conductivity, a wide band gap, and chemical and thermal inertness. However, because of its aversion to chemical modification, its applications have not progressed as much as those of carbon nanomaterials. In this manuscript, we show the functionalization of hexagonal boron nitride using alkyl halides in strongly reducing conditions (Billups–Birch conditions). The tunability of the Billups–Birch reaction is demonstrated by alkylating hexagonal boron nitride with 1-bromododecane and varying equivalents of Li to BN. We found that using a 1:20 BN/Li ratio yields the highest chemical modification, as demonstrated using thermogravimetric analysis and Fourier transform infrared spectroscopy, and supported by X-ray photoelectron spectroscopy. Imaging of the functionalized h-BN (fh-BN) revealed that its sheets exfoliate better in isopropanol than pristine h-BN, which displays highly stacked nanostructures. Moreover, bearing alkyl chains confers the nanosheets with improved dispersibility in nonpolar solvents, such as dodecane, and allows the formation of hydrophobic films.