• Péron, Nicolas
• Brochard-Wyart, Françoise
• Duval, Hervé

Abstract

We report new experimental results on the dewetting of a mercury film (A) intercalated between a glass slab and an external nonmiscible liquid phase (B) under conditions of a large equilibrium contact angle. The viscosity of the external phase, η_B, was varied over 7 orders of magnitude. We observe a transition between two regimes of dewetting at a threshold viscosity of η_B* ≈ (ρ_Ae|S̃|)^1/2, where ρ_A is the mercury density, e is the film thickness, and |S̃| is the effective spreading coefficient. For η_B < η_B*, the regime is inertial. The velocity of dewetting is constant and ruled by Culick’s law, V ≈ (|S̃|/(ρ_Ae))^1/2. Capillary waves were observed at high dewetting velocities: they are a signature of hydraulic shock. For η_B > η_B*, the regime is viscous. The dewetting velocity is constant and scales as V ≈ |S̃|/η_B in the limit of large η_B. We interpret this regime by a balance between the surface energy released during dewetting and the viscous dissipation in the surrounding liquid.

Topics

• density
• impedance spectroscopy
• surface
• glass
• glass
• viscosity
• liquid phase
• surface energy
• Mercury