Spontaneous Formation of Air Nanobubbles on Hydrocarbons Deposited on the Au(111)/Water Interface

We have observed surface features on hydrocarbons deposited on Au(111) from the laboratory atmosphere in water and in a sodium chloride aqueous solution, using tapping mode atomic force microscopy (TMAFM). TMAFM images of the Au(111)/water interface reveal that the features are pancake-shaped structures with the range of measured dimensions of 20–150 nm in width and 0.5–20 nm in height, and that many features reappear at almost the same sites immediately after the disruption of the features by contact mode AFM imaging. The results of our TMAFM observations imply that the features are nanosized bubbles as those reported previously, and that dissolved gas nucleates at specific sites of the hydrophobized Au(111) surface at low, temporal gas supersaturations under atmospheric pressure.