Characterization of Surface Nanobubbles

In this work we characterize surface nanobubbles on hydrophobic surface in water by Atomic Force Microscopy (AFM) operated in the tapping mode. A connection between the formation of nanobubbles and the surface topography is presented. Together with large contact angle of nanobubbles, which determines their shape, the surface topology may support the surprising stability of nanobubbles. It is shown that the properties of the nanobubbles and their density are sensitive to the gas concentration and type. We show that different surface treatments also influence nanobubbles in formation and shape. Next, adding surfactants (2-butanol) causes nanobubbles to shrink, as expected from the Laplace equation. Finally, we show that exchanging alcohols by water on the surface strongly encourages the formation of nanobubbles.