Wettability of net C, net W and net Y: a molecular dynamics simulation study

Abstract

The experimental synthesis of biphenylene, a two-dimensional carbon allotrope, theoretically predicted in 1997, took place in 2021. Biphenylene is also called net C. Two close relatives of this structure, known as net W and net Y, have not yet been experimentally synthesized. In this article, the wettability properties of these three carbon allotropes are investigated, using molecular dynamics simulation. The electronic and mechanical properties of these allotropes have been extensively studied, but their wettability properties are unknown. The chemical structure of the three allotropes is similar and contain four, six, and eight carbon membered rings. The results of molecular dynamics calculations with reactive potential show that net C, net W and net Y are hydrophobic substrates with contact angles of 122.3° ± 1.3°, 126.2° ± 1.3° and 127.8° ± 1.2°, respectively. The droplets on the above-mentioned substrates have a completely layered structure. That is, the water molecules inside the droplet are completely placed in certain layers. Calculating the order parameter for water molecules shows that the degree of water molecules' tetrahedrality on all three substrates is exactly the same. In terms of hydrogen bonding at the interface, the three substrates act identically and show almost the same effect. The droplet displacement is the highest on net W and the lowest on net Y. Furthermore, the van der Waals potential on all three substrates has been scanned. It is demonstrated that the amount of droplet displacement on the surface is inversely related to the surface density of the potential peaks.