Evaporation-driven dewetting of a liquid film
Résumé
We study the dynamics of evaporating ethanol films deposited by a receding liquid
meniscus. The films are surrounded by pure vapor in a capillary heated above the saturation
temperature. We observe the substrate dewetting with the dewetting ridge in spite of the
complete wetting at equilibrium. The dewetting is caused by a high contact angle (∼30◦)
induced by evaporation. The obtained values agree with a theory proposed earlier. The film
shape is measured with both grid deflection technique and interferometry. The phenomenon
is convenient to observe inside a capillary with an axial thermal gradient. When the capillary
is closed at one end and open at another to a constant pressure reservoir, the meniscus
oscillations are known to appear spontaneously. Such a system is the simplest version of
an industrial device called a pulsating heat pipe. The effect is general and can be used in
any system to control the wetting properties
Domaines
Physique [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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