Surface morphology effect on the evaporation of water on graphene oxide: A molecular dynamics study

Graphene oxide (GO) has drawn intensive attention recently in accelerating water evaporation, which can be highly beneficial for desalination, steam generation and other related industrial applications. The unique surface structure of GO, which comprises a mixture of both hydrophilic oxidized and hydrophobic pristine regions, has significant potential for evaporation enhancement, and many recent studies had investigated the evaporation behavior of water on the GO surface as well as the effect of the oxidized functional groups. However, the effect due to the surface roughness of the GO sheets, which is inevitable during the synthesis and fabrication of the structure, has not been considered so far. In this study, we performed molecular dynamics simulations to investigate the evaporation mechanism of water on a corrugated GO surface. We show that the surface roughness can play a vital role in the contact distribution of the water molecules, thus leading to the further enhancement of evaporation flux compared to a flat surface. The effects of the water drop size and distribution of the oxidized groups are also examined. The results from this study provide useful guidelines for the design of nanostructures in evaporation and steam generation applications.