Anisotropic\nWetting and Diffusion Behavior of Water\nDroplets on Biphenylene Compared to Graphene

We comparatively studied the wetting behavior of water\ndroplets\non graphene and biphenylene using molecular dynamics simulations.\nThe research showed that pristine biphenylene (BPN), unlike graphene,\nexhibits greater hydrophobicity and anisotropic wettability. This\nspecific anisotropy can be tuned by the layer number and vacancy concentration.\nParticularly, there was a decrease in the water contact angle with\nincreasing BPN layer number, highlighting the importance of water–BPN\ninteractions. As the concentration of vacancies increases, the contact\nangle increases both along the zigzag direction and the armchair direction,\nwhile the anisotropy decreases. In planar defective biphenylene heterojunctions,\nwater droplets spontaneously move from the defective area to the pristine\narea, where the zigzag direction exhibits a larger energy gradient\ncompared to the armchair direction, leading to a faster movement of\nwater droplets in the zigzag direction. The energy factor plays an\nimportant role in the directional movement of the water droplets.\nOur study explores new 2D materials with strong hydrophobicity and\nhighlights the direction-dependent wetting behavior of biphenylene.