On the shape of a droplet in a wedge: new insight from electrowetting

Davood Baratian, Andrea Cavalli, Henricus T.M. van den Ende, Friedrich Gunther Mugele

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17 Citations (Scopus)
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Abstract

The equilibrium morphology of liquid drops exposed to geometric constraints can be rather complex. Even for simple geometries, analytical solutions are scarce. Here, we investigate the equilibrium shape and position of liquid drops confined in the wedge between two solid surfaces at an angle α. Using electrowetting, we control the contact angle and thereby manipulate the shape and the equilibrium position of aqueous drops in ambient oil. In the absence of contact angle hysteresis and buoyancy, we find that the equilibrium shape is given by a truncated sphere, at a position that is determined by the drop volume and the contact angle. At this position, the net normal force between drop and the surfaces vanishes. The effect of buoyancy gives rise to substantial deviations from this equilibrium configuration which we discuss here as well. We eventually show how the geometric constraint and electrowetting can be used to position droplets inside a wedge in a controlled way, without mechanical actuation
Original languageEnglish
Pages (from-to)7717-7721
JournalSoft matter
Volume11
Issue number39
DOIs
Publication statusPublished - 2015

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wedges
Contact angle
Buoyancy
buoyancy
Liquids
actuation
solid surfaces
Hysteresis
Oils
oils
hysteresis
deviation
Geometry
geometry
configurations

Keywords

  • METIS-312385
  • IR-97807

Cite this

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On the shape of a droplet in a wedge: new insight from electrowetting. / Baratian, Davood; Cavalli, Andrea; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther.

In: Soft matter, Vol. 11, No. 39, 2015, p. 7717-7721.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - On the shape of a droplet in a wedge: new insight from electrowetting

AU - Baratian, Davood

AU - Cavalli, Andrea

AU - van den Ende, Henricus T.M.

AU - Mugele, Friedrich Gunther

PY - 2015

Y1 - 2015

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AB - The equilibrium morphology of liquid drops exposed to geometric constraints can be rather complex. Even for simple geometries, analytical solutions are scarce. Here, we investigate the equilibrium shape and position of liquid drops confined in the wedge between two solid surfaces at an angle α. Using electrowetting, we control the contact angle and thereby manipulate the shape and the equilibrium position of aqueous drops in ambient oil. In the absence of contact angle hysteresis and buoyancy, we find that the equilibrium shape is given by a truncated sphere, at a position that is determined by the drop volume and the contact angle. At this position, the net normal force between drop and the surfaces vanishes. The effect of buoyancy gives rise to substantial deviations from this equilibrium configuration which we discuss here as well. We eventually show how the geometric constraint and electrowetting can be used to position droplets inside a wedge in a controlled way, without mechanical actuation

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KW - IR-97807

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DO - 10.1039/C5SM01511A

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