Mechanisms of equilibrium shape transitions of liquid droplets in electrowetting

Drygiannakis, AI; Papathanasiou, AG; Boudouvis, AG

dc.contributor.author	Drygiannakis, AI	en
dc.contributor.author	Papathanasiou, AG	en
dc.contributor.author	Boudouvis, AG	en
dc.date.accessioned	2014-03-01T01:28:45Z
dc.date.available	2014-03-01T01:28:45Z
dc.date.issued	2008	en
dc.identifier.issn	0021-9797	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18955
dc.subject	Contact angle	en
dc.subject	Drop breakup	en
dc.subject	Electrowetting	en
dc.subject	Finite element method	en
dc.subject	Turning point	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	Bifurcation (mathematics)	en
dc.subject.other	Boundary element method	en
dc.subject.other	Bridges	en
dc.subject.other	Drop breakup	en
dc.subject.other	Drop formation	en
dc.subject.other	Drops	en
dc.subject.other	Electrodes	en
dc.subject.other	Hydraulics	en
dc.subject.other	Hydrodynamics	en
dc.subject.other	Joining	en
dc.subject.other	Liquids	en
dc.subject.other	Mechanisms	en
dc.subject.other	Metallizing	en
dc.subject.other	Nonlinear equations	en
dc.subject.other	Solutions	en
dc.subject.other	Turning	en
dc.subject.other	Applied voltages	en
dc.subject.other	Capillary bridges	en
dc.subject.other	Contact angle	en
dc.subject.other	Critical voltages	en
dc.subject.other	Electrode plates	en
dc.subject.other	Electrowetting	en
dc.subject.other	Equilibrium shapes	en
dc.subject.other	Finite element method	en
dc.subject.other	Free-boundary problems	en
dc.subject.other	Governing equations	en
dc.subject.other	Liquid bridges	en
dc.subject.other	Liquid droplets	en
dc.subject.other	Parameter regions	en
dc.subject.other	Pendant drops	en
dc.subject.other	Relative positioning	en
dc.subject.other	Shape transitions	en
dc.subject.other	Solution spaces	en
dc.subject.other	Turning point	en
dc.subject.other	Turning points	en
dc.subject.other	Fluid mechanics	en
dc.subject.other	article	en
dc.subject.other	electric potential	en
dc.subject.other	electrode	en
dc.subject.other	electrowetting	en
dc.subject.other	equilibrium constant	en
dc.subject.other	finite element analysis	en
dc.subject.other	hydrostatic pressure	en
dc.subject.other	illumination	en
dc.subject.other	liquid	en
dc.subject.other	liquid droplet	en
dc.subject.other	priority journal	en
dc.subject.other	solution and solubility	en
dc.title	Mechanisms of equilibrium shape transitions of liquid droplets in electrowetting	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jcis.2008.06.061	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jcis.2008.06.061	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	Liquid droplets bridging the gap between two dielectric-coated horizontal electrode plates suffer breakup instabilities when a voltage applied between the electrodes exceeds a threshold. Interestingly enough, broken liquid bridges (i.e. a pair of a sessile and a pendant drop) can spontaneously rejoin if the voltage is still applied to the electrodes. Here we study the electro-hydrostatics of the liquid bridges in the joined or broken state and we illuminate the mechanisms of the shape transitions that lead to bridge rupture or droplet joining. The governing equations of the capillary electro-hydrostatics form nonlinear and free boundary problems which are solved numerically by the Galerkin/finite element method. On one hand, we found that capillary bridges become unstable at a turning point bifurcation in their solution space. The solutions past the turning point are unstable and the instability signals the bridge rupture. On the other hand, the separate droplets approach each other as the applied voltage increases. However, solutions become unstable past a Critical Voltage at a turning point bifurcation and the droplets join. By studying the relative position of the turning points corresponding to bridge rupture and droplet joining, respectively, we define parameter regions where stable bridges or separate droplets or oscillations between them can be realized. (c) 2008 Elsevier Inc. All rights reserved.	en
heal.publisher	ACADEMIC PRESS INC ELSEVIER SCIENCE	en
heal.journalName	Journal of Colloid and Interface Science	en
dc.identifier.doi	10.1016/j.jcis.2008.06.061	en
dc.identifier.isi	ISI:000259243600022	en
dc.identifier.volume	326	en
dc.identifier.issue	2	en
dc.identifier.spage	451	en
dc.identifier.epage	459	en