Visualization of Small Water Droplets on Surfaces with Different Degree of Wettability by Using Cryo-Scanning Electron Microscopy

Cryo-scanning electron microscopy (Cryo-SEM) was applied to visualize mm- and μm-sized water droplets on surfaces differing in their wettability. The shape of droplets varied depending on the surface energy of surfaces studied. On superhydrophobic surfaces, mostly complete drops could be observed. In the Cryo-SEM samples on hydrophilic surfaces, where ice was sublimated, the shape and original size of droplets and water films was recognised due to network- or foam-like residues present in water. The snapshots of dynamical processes, such as condensation or coalescence, were visualized at a high resolution.