Interfaces and Free Boundaries

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Volume 11, Issue 2, 2009, pp. 259–290
DOI: 10.4171/IFB/211

Published online: 2009-06-30

On a phase-field model for electrowetting

Christof Eck[1], M. Fontelos[2], Günther Grün[3], F. Klingbeil[4] and O. Vantzos[5]

(1) Universität Stuttgart, Germany
(2) Universidad Autónoma de Madrid, Spain
(3) Universität Erlangen-Nünberg, Germany
(4) Universität Erlangen-Nünberg, Germany
(5) Universidad Autónoma de Madrid, Spain

The term electrowetting is commonly used for phenomena where shape and wetting behavior of liquid droplets are changed by the application of electric fields. We develop and analyze a model for electrowetting that combines the Navier–Stokes system for fluid flow, a phase-field model of Cahn–Hilliard type for the movement of the interface, a charge transport equation, and the potential equation of electrostatics. The model is derived with the help of a variational principle due to Onsager and conservation laws. A modification of the model with the Stokes system instead of the Navier– Stokes system is also presented. The existence of weak solutions is proved for several cases in two and three space dimensions, either with non-degenerate or with degenerate electric conductivity vanishing in the droplet exterior. Some numerical examples in two space dimensions illustrate the applicability of the model.

Keywords: Electrowetting, phase-field model, Navier–Stokes system, Cahn–Hilliard model, free boundary problem in PDE, existence of weak solutions

Eck Christof, Fontelos M., Grün Günther, Klingbeil F., Vantzos O.: On a phase-field model for electrowetting. Interfaces Free Bound. 11 (2009), 259-290. doi: 10.4171/IFB/211