Evaporation-driven dewetting of a liquid film

L. Fourgeaud (1, 2) , E. Ercolani (2) , J. Duplat (2) , P. Gully (2) , Vadim S. Nikolayev (3)

1 PSA - PSA Peugeot Citroën
2 SBT - Service des Basses Températures
3 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

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

Domains: Physics [physics]

L. Fourgeaud, E. Ercolani, J. Duplat, P. Gully, Vadim S. Nikolayev. Evaporation-driven dewetting of a liquid film. Physical Review Fluids, 2016, 1, pp.41901(R). ⟨10.1103/PhysRevFluids.1.041901⟩. ⟨cea-01485388⟩