Environmentally Friendly and All-Dry Hydrophobic Patterning of Graphene Oxide for Fog Harvesting

This study examines the fog-harvesting ability of graphene oxide surfaces patterned by hydrophobic domains. The samples were prepared from graphene deposited using low pressure chemical vapor deposition, which was later plasma oxidized to obtain hydrophilic graphene oxide (GO) surfaces. Hydrophobic domains on GO surfaces were formed by initiated CVD (iCVD) of a low-surface-energy poly(perfluorodecyl alkylate) (PPFDA) polymer. Hence, patterned surfaces with hydrophobic/hydrophilic contrast were produced with ease in an all-dry manner. The structures of the as-deposited graphene and PPFDA films were characterized using Raman and Fourier transform infrared spectrophotometer analyses, respectively. The fog harvesting performance of the samples was measured using the fog generated by a nebulizer, in which the average diameter of the fog droplets is comparable to meteorological fog. According to the fog harvesting experiment results, 100 cm² of the as-patterned surface can collect fog up to 2.5 L in 10 h in a foggy environment. Hence, hydrophilic/hydrophobic patterned surfaces in this study can be considered as promising fog harvesting materials. Both CVD techniques used in the production of hydrophilic/hydrophobic patterned surfaces can be easily applied to the production of large-scale materials.