Molecular dynamics study of water evaporation enhancement through a capillary graphene; bilayer with tunable hydrophilicity*

The acceleration of the rate of water evaporation is critically important to thermal processes in various industrial and manufacturing applications. Recently, graphene nanostructures have exhibited promising potential in the evaporation enhancement due to their porous structure, which can take advantage of the capillary effect. However, the mechanism of water evaporation through graphene nanochannels and the effect of surface properties remain unexplored. The present study (Kieu et al., 2018, Applied Surface Science, 452, 372-380) investigates the evaporation behavior of nanoscale water through a vertically aligned graphene bilayer using molecular dynamics simulations. The effects of the capillary layer distance and temperature are also examined in detail. The results show that significant enhancement of evaporation occurs when the graphene bilayer is tuned from hydrophobic to hydrophilic, and the evaporation behavior is controlled by two main factors, namely, the morphology of the liquid-gas interface and the interaction energy between the water molecules and the graphene layer.