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Published on: April 17, 2018
Wetting of Two-Component Drops: Marangoni Contraction Versus Autophobing
Michiel A Hack1, Wojciech Kwieciński2, Olinka Ramírez-Soto3
1Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Wetting properties of surfactant-like alkanediol-water mixtures are surprisingly complex. Two distinct mechanisms, Marangoni contraction and autophobing, determine contact angles, with molecular structure playing a key role.
Area of Science:
- Physico-chemical hydrodynamics
- Surface science
- Colloid and interface science
Background:
- Wetting properties of multicomponent liquids are vital for industrial applications.
- Mechanisms governing contact angles in complex mixtures, like those with surfactants, are not fully understood.
Purpose of the Study:
- Investigate the wetting behavior of two-component drops composed of vicinal alkanediols and water.
- Elucidate the underlying mechanisms responsible for the observed contact angles in these surfactant-like mixtures.
Main Methods:
- Experimental analysis of contact angles for alkanediol-water mixtures on solid substrates.
- Identification and characterization of hydrodynamic and molecular phenomena influencing wetting.
Main Results:
- Alkanediol-water mixtures exhibit surprisingly large contact angles.
- Contact angle is governed by a interplay between Marangoni contraction (hydrodynamic) and autophobing (molecular).
- The competition between these effects can suppress Marangoni contraction.
Conclusions:
- Wetting behavior in these systems is dictated by a dual mechanism involving both fluid dynamics and molecular interactions.
- Molecular structure significantly impacts physico-chemical hydrodynamics and wetting phenomena.
- Understanding these competing effects is crucial for controlling interfacial properties in industrial processes.
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