Growth dynamics and gas transport mechanism of nanobubbles in graphene liquid cells

• Published in: Nature communications Vol. 6; no. 1; p. 6068
• Main Authors: Shin, Dongha, Park, Jong Bo, Kim, Yong-Jin, Kim, Sang Jin, Kang, Jin Hyoun, Lee, Bora, Cho, Sung-Pyo, Hong, Byung Hee, Novoselov, Konstantin S
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.02.2015; Nature Publishing Group
• Subjects: 639/766/25; 639/925/357/918; 639/925/927/351; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms7068

Formation, evolution and vanishing of bubbles are common phenomena in nature, which can be easily observed in boiling or falling water, carbonated drinks, gas-forming electrochemical reactions and so on. However, the morphology and the growth dynamics of the bubbles at nanoscale have not been fully investigated owing to the lack of proper imaging tools that can visualize nanoscale objects in the liquid phase. Here, we demonstrate for the first time that the nanobubbles in water encapsulated by graphene membrane can be visualized by in-situ ultra-high vacuum transmission electron microscopy. Our microscopic results indicate two distinct growth mechanisms of merging nanobubbles and the existence of a critical radius of nanobubbles that determines the unusually long stability of nanobubbles. Interestingly, the gas transport through ultrathin water membranes at nanobubble interface is free from dissolution, which is clearly different from conventional gas transport that includes condensation, transmission and evaporation. Nanobubbles in liquid phase are puzzling, because their internal pressure is estimated to be unphysically large. Here, Shin et al . visualize the dynamics of nanobubbles in water encapsulated by graphene membrane and show fast gas diffusion through ultrathin water layer between two coalescing bubbles.