Dewetting

In fluid mechanics, dewetting is one of the processes that can occur at a solid–liquid or liquid–liquid interface. Generally, dewetting describes the rupture of a thin liquid film on the substrate (either a liquid itself, or a solid) and the formation of droplets. The opposite process—spreading of a liquid on a substrate—is called wetting. The factor determining the spontaneous spreading and dewetting for a drop of oil placed on a liquid substrate (water here) with ambient gas, is the so-called spreading coefficient ${\displaystyle S}$:

where ${\displaystyle \gamma _{\text{gw}}}$ is the gas-water surface tension, ${\displaystyle \gamma _{\text{go}}}$ is the gas-oil surface tension and ${\displaystyle \gamma _{\text{ow}}}$ is the oil water surface tension (measured on the fluids before they are brought in contact with each other)

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