Modulating the Water Contact Angle Using Surface Roughness: Interfacial Properties of Hexagonal Boron Nitride Surfaces

Abstract

Hexagonal boron nitride (hBN) exhibits immense potential in H 2 O-related technologies, but its interaction with H 2 O, especially on rough surfaces, remains unclear. This study unravels the influence of surface roughness and force field selection on hBN wettability using molecular dynamics (MD) simulations. We leverage quantum mechanical calculations to accurately capture the hBN surface charge distribution and combine it with free energy calculations via MD simulations for the hBN−H 2 O interfaces. Incorporating surface roughness into the model yields results in close agreement with the experimental contact angle of 66°for H 2 O using FF-3 force fields, validating the simulation approach. However, this approach can yield an unrealistic water contact angle (WCA) of 0°for FF-2 force fields, highlighting the crucial role of force field selection and realistic surface representations. We further dissect the impact of roughness on the WCA, identifying the individual contributions of electrostatic and Lennard-Jones interactions to the work of adhesion. This research investigates the combined impact of surface roughness and force fields on interfacial properties, providing new possibilities for the advancement and optimization of desalination.