Extraordinarily enhanced evaporation of water droplets on graphene-nanostructured coated surfaces

Functionalized graphene coating possessing the unique property of ultrafast water permeation manifests itself in enhancing the evaporation heat transfer. The intermolecular interactions between the intercalated water molecules with the hydrophobic carbon atoms and the oxygenated functional groups in the graphene nanocapillaries facilitate the magnificent spreadability and permeability of water on a heated surface. The fast water permeation property of graphene can be controlled through a thermal curing process at different curing temperatures. Here we experimentally investigate the application of graphene nanoplatelets (GNPs) coatings for the enhancement of evaporation of small sessile water droplets at sub-boiling temperatures. The ultrafast water permeation within the functionalized nanostructured GNPs facilitates the fast absorption of latent heat of evaporation, leading to the anomalously effective filmwise evaporation. Ultimately, the cooling effectiveness of a water droplet on the GNPs-coated surface is extraordinarily enhanced by an unprecedented maximum of 4866% at a surface temperature of 75 °C compared against the bare surface. These results envision the great potential of graphene-based coatings to address the issues of increased heat generated from the high power density electronics, leading to enhanced performance and extended component lifespans.