Wettability of Tetrahexcarbon: MD, DFT, and AIMD Approaches

Graphene and its allotropes have attracted attention due to their special electronic, mechanical, and thermal properties. Numerous studies investigate their wetting behavior. Tetrahexcarbon (THC) is a new carbon allotrope and is obtained from pentagraphene. This research, examines THC's wettability properties using reactive molecular dynamics (MD) and density functional theory (DFT) simulations. The results of molecular dynamics simulation reveal that THC is a hydrophobic substrate with a contact angle of 113.4° ± 2.8°. Using molecular dynamics, this research also evaluates quantities such as contact diameter, dipole moment, and density profile of water droplet. In addition, hydrogen and oxygen atoms' distribution functions, hydrogen bonds, path of the droplet's center of mass, and potential energy surface are presented. According to the simulation results, the droplet's structure on THC is slightly layered. Also, the water molecules' orientations in the interface are such that they do not allow the hydrogen bonds to form between water molecules and the THC substrate. The results of MD show that there are two different behavioral patterns for the hydrogen bonds between and within the water droplet's layers. Furthermore, this research utilizes DFT and AIMD in order to show how a water molecule interacts with THC. DFT exhibits that the water molecule's hydrogen atoms are toward the substrate. But an opposite configuration happens in the droplet–THC interface. The results of the atoms-in-molecules (AIM) theory indicate that there is a weak interaction between the water molecules and the THC substrate. The thermochemical results reveal that water molecules' adsorption is within the range of physical adsorption. Finally, NBO analysis shows that the THC's carbon atoms have a permanent partial charge. These results confirm that the THC is a hydrophobic material.