Analytic model for the electrowetting properties of oil-water-solid systems

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Abstract

The competitive wetting of oil and aqueous electrolytes on solid surfaces depends strongly on the surface charge of the solid-water and the water-oil interface. This charge density is generally not known a priori but changes as ions adsorb or desorb from or to the interfaces, depending on the composition of the fluid and the thickness of thin films of the aqueous phase that frequently arise on hydrophilic surfaces, such as minerals. We analyze the wettability of such systems by coupling standard Derjaguin-Landau-Verwey-Overbeek theory to a linearized charge regulation model. The latter is found to play an important role. By linearizing electrostatic interactions as well, we obtain a fully analytic description of transitions between different wetting scenarios as a function of the surface potentials at infinite separation and the charge regulation parameters of the two interfaces. Depending on the specific values of the regulation parameters, charge regulation is found to extend the parameter range of partial wetting and complete wetting at the expense of pseudopartial wetting and metastable wetting configurations, respectively. A specific implementation of the model is discussed for mica-water-alkane systems that was investigated in recent experiments.
Original languageEnglish
Article number042606
Pages (from-to)1-11
JournalPhysical review E: Statistical, nonlinear, and soft matter physics
Volume93
Issue number042606
DOIs
Publication statusPublished - 2016

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Wetting
wetting
oils
Water
Charge
water
Model
Wettability
Surface Potential
Electrolyte
wettability
mica
solid surfaces
Electrostatics
alkanes
Thin Films
minerals
electrolytes
electrostatics
Partial

Keywords

  • METIS-319527
  • IR-102485

Cite this

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title = "Analytic model for the electrowetting properties of oil-water-solid systems",
abstract = "The competitive wetting of oil and aqueous electrolytes on solid surfaces depends strongly on the surface charge of the solid-water and the water-oil interface. This charge density is generally not known a priori but changes as ions adsorb or desorb from or to the interfaces, depending on the composition of the fluid and the thickness of thin films of the aqueous phase that frequently arise on hydrophilic surfaces, such as minerals. We analyze the wettability of such systems by coupling standard Derjaguin-Landau-Verwey-Overbeek theory to a linearized charge regulation model. The latter is found to play an important role. By linearizing electrostatic interactions as well, we obtain a fully analytic description of transitions between different wetting scenarios as a function of the surface potentials at infinite separation and the charge regulation parameters of the two interfaces. Depending on the specific values of the regulation parameters, charge regulation is found to extend the parameter range of partial wetting and complete wetting at the expense of pseudopartial wetting and metastable wetting configurations, respectively. A specific implementation of the model is discussed for mica-water-alkane systems that was investigated in recent experiments.",
keywords = "METIS-319527, IR-102485",
author = "Andrea Cavalli and B. Bera and {van den Ende}, {Henricus T.M.} and Mugele, {Friedrich Gunther}",
year = "2016",
doi = "10.1103/PhysRevE.93.042606",
language = "English",
volume = "93",
pages = "1--11",
journal = "Physical review E: covering statistical, nonlinear, biological, and soft matter physics",
issn = "2470-0045",
publisher = "American Physical Society",
number = "042606",

}

Analytic model for the electrowetting properties of oil-water-solid systems. / Cavalli, Andrea; Bera, B.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther.

In: Physical review E: Statistical, nonlinear, and soft matter physics, Vol. 93, No. 042606, 042606, 2016, p. 1-11.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Analytic model for the electrowetting properties of oil-water-solid systems

AU - Cavalli, Andrea

AU - Bera, B.

AU - van den Ende, Henricus T.M.

AU - Mugele, Friedrich Gunther

PY - 2016

Y1 - 2016

N2 - The competitive wetting of oil and aqueous electrolytes on solid surfaces depends strongly on the surface charge of the solid-water and the water-oil interface. This charge density is generally not known a priori but changes as ions adsorb or desorb from or to the interfaces, depending on the composition of the fluid and the thickness of thin films of the aqueous phase that frequently arise on hydrophilic surfaces, such as minerals. We analyze the wettability of such systems by coupling standard Derjaguin-Landau-Verwey-Overbeek theory to a linearized charge regulation model. The latter is found to play an important role. By linearizing electrostatic interactions as well, we obtain a fully analytic description of transitions between different wetting scenarios as a function of the surface potentials at infinite separation and the charge regulation parameters of the two interfaces. Depending on the specific values of the regulation parameters, charge regulation is found to extend the parameter range of partial wetting and complete wetting at the expense of pseudopartial wetting and metastable wetting configurations, respectively. A specific implementation of the model is discussed for mica-water-alkane systems that was investigated in recent experiments.

AB - The competitive wetting of oil and aqueous electrolytes on solid surfaces depends strongly on the surface charge of the solid-water and the water-oil interface. This charge density is generally not known a priori but changes as ions adsorb or desorb from or to the interfaces, depending on the composition of the fluid and the thickness of thin films of the aqueous phase that frequently arise on hydrophilic surfaces, such as minerals. We analyze the wettability of such systems by coupling standard Derjaguin-Landau-Verwey-Overbeek theory to a linearized charge regulation model. The latter is found to play an important role. By linearizing electrostatic interactions as well, we obtain a fully analytic description of transitions between different wetting scenarios as a function of the surface potentials at infinite separation and the charge regulation parameters of the two interfaces. Depending on the specific values of the regulation parameters, charge regulation is found to extend the parameter range of partial wetting and complete wetting at the expense of pseudopartial wetting and metastable wetting configurations, respectively. A specific implementation of the model is discussed for mica-water-alkane systems that was investigated in recent experiments.

KW - METIS-319527

KW - IR-102485

U2 - 10.1103/PhysRevE.93.042606

DO - 10.1103/PhysRevE.93.042606

M3 - Article

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SP - 1

EP - 11

JO - Physical review E: covering statistical, nonlinear, biological, and soft matter physics

JF - Physical review E: covering statistical, nonlinear, biological, and soft matter physics

SN - 2470-0045

IS - 042606

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