This
study introduces an anisotropic interfacial potential that
provides an accurate description of the van der Waals (vdW) interactions
between water and hexagonal boron nitride (h-BN)
at their interface. Benchmarked against the strongly constrained and
appropriately normed functional, the developed force field demonstrates
remarkable consistency with reference data sets, including binding
energy curves and sliding potential energy surfaces for various configurations
involving a water molecule adsorbed atop the h-BN
surface. These findings highlight the significant improvement achieved
by the developed force field in empirically describing the anisotropic
vdW interactions of the water/h-BN heterointerfaces.
Utilizing this anisotropic force field, molecular dynamics simulations
demonstrate that atomically flat, pristine h-BN exhibits
inherent hydrophobicity. However, when atomic-step surface roughness
is introduced, the wettability of h-BN undergoes
a significant change, leading to a hydrophilic nature. The calculated
water contact angle (WCA) for the roughened h-BN
surface is approximately 64°, which closely aligns with experimental
WCA values ranging from 52° to 67°. These findings indicate
the high probability of the presence of atomic steps on the surfaces
of the experimental h-BN samples, emphasizing the
need for further experimental verification. The development of the
anisotropic interfacial force field for accurately describing interactions
at the water/h-BN heterointerfaces is a significant
advancement in accurately simulating the wettability of two-dimensional
(2D) materials, offering a reliable tool for studying the dynamic
and transport properties of water at these interfaces, with implications
for materials science and nanotechnology.