Theory of wetting-induced fluid entrainment by advancing contact lines on dry surfaces

Abstract

We report on the onset of fluid entrainment when a contact line is forced to advance over a dry solid of arbitrary wettability. We show that entrainment occurs at a critical advancing speed beyond which the balance between capillary, viscous and contact line forces sustaining the shape of the interface is no longer satisfied. Wetting couples to the hydrodynamics by setting both the morphology of the interface at small scales and the viscous friction of the front. We find that the critical deformation that the interface can sustain is controlled by the friction at the contact line and the viscosity contrast between the displacing and displaced fluids, leading to a rich variety of wetting-entrainment regimes. We discuss the potential use of our theory to measure contact-line forces using atomic force microscopy, and to study entrainment under microfluidic conditions exploiting colloid-polymer fluids of ultra-low surface tension.

5 pages, 4 figures

References in corpus (5)

• Colloidal Jamming at Interfaces: a Route to Fluid-bicontinuous Gels
• Making a splash with water repellency
• A variational approach to the moving contact line hydrodynamics
• Controlled interfacial assembly of 2D curved colloidal crystals and jammed shells
• Free surface flows with large slopes: beyond lubrication theory

Cited by in corpus (2)

• Revisiting the Saffman-Taylor experiment: imbibition patterns and liquid-entrainment transitions
• Steering droplets on substrates using moving steps in wettability