Enhanced film-wise water evaporation through graphene nanostructures: A molecular dynamics insight

The functionalization of graphene nanoplatelets (GNPs) with hydrophilic hydroxyl groups through thermal curing imparts hydrophilicity and water-permeability to the GNPs, opening doors to promising applications in phase-change cooling and pervaporation water filtration. This investigation employs molecular dynamics simulations to uncover the mechanisms by which the hydroxyl functional groups enhance the film-wise water evaporation on GNPs. The introduction of hydroxyl groups disrupts the hydrogen bond network among water molecules, creating a conducive environment for enhanced evaporation. Hydroxyl-functionalized GNPs act as hub-like platforms at their edges, expediting the transport and evaporation of water. The increased hydrophilicity fosters a more efficient liquid-gas interface for water clusters. Furthermore, the substantial presence of hydroxyl groups reduces the Kapitza resistance between GNPs and water, accelerating water heating. This study also examines the impact of the attachment location of hydroxyl groups, highlighting that edge attachment, as opposed to across the graphene basal plane, offers a more promising approach for augmenting water evaporation efficiency. This study enhances the comprehension of the role of hydroxyl functionalization in promoting water evaporation on GNPs and provides valuable insights for optimizing graphene-based materials in applications requiring efficient water evaporation and transport.