Wetting properties of thin films of exfoliated hexagonal boron nitride in different solvents

Hexagonal boron nitride is a 2D material with excellent properties, such as large band gap, high thermal and chemical stability, transparency, and high oxidation and corrosion resistance. These properties make h-BN a suitable candidate to be used in the development of advanced coatings. However, as for other nanomaterials, tailoring and controlling the properties of h-BN is a fundamental key to its application into several fields. Here, the wetting properties of h-BN were investigated when it is exfoliated by ultrasonic cavitation in different solvents such as isopropyl alcohol (IPA), dioxane (Dx), N-methyl pyrrolidone (NMP) and dimethyl formamide (DMF). The wetting properties of the different h-BN materials were determined by measuring the water contact angle (WCA) of h-BN thin films deposited on silicon dioxide. Different contact angles were observed for each sample, the different WCA values are explained by the differences in the structure and roughness of the thin film surfaces obtained just by changing the solvent during exfoliation. These surface properties were characterized by optic and transmission electronic microscopy (TEM) as well as atomic force microscopy (AFM).