Controllable manipulation of bubbles in water by using underwater superaerophobic graphene-oxide/gold-nanoparticle composite surfaces

Manipulation of bubbles in water is of great importance in the mineral industry, oil production and separation, wastewater treatments, boiling processes, biological cell incubations, microfluidics and miniature reactor technologies. Generally, bubbles in an aqueous environment are inclined to stick to the channel walls, resulting in blockage and energy-consuming treatments. Herein, we report the fabrication of low-adhesion graphene-oxide (GO)/gold-nanoparticle (GNP) hybrid films with a good underwater superaero-phobicity, which have the ability to arbitrarily manipulate bubbles in water. Owing to the hydrophilic nature of GO nanosheets and hierarchical structures of aggregated GNPs, the GO/GNP hybrid films showed low adhesion towards bubbles in water. Thus, bubbles could be freely manipulated using homemade tools coated with these low-adhesion, underwater superaerophobic GO/GNP hybrid films. The controlled 1D and 2D movements of one bubble and merging/reaction of two bubbles can be achieved. This study provides a new avenue to design new strategies for bubble manipulations, and further extends the application of superwettable 2D materials in interface fields involving gas phases.