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Finite conductivity effects and apparent contact angle saturation in AC electrowetting

Published online by Cambridge University Press:  26 February 2011

Abishek Kumar ,
Manuela Pluntke ,
Benjamin Cross ,
Jean-Christophe Baret  and
Frieder Mugele
Abishek Kumar
Affiliation:
A.kumar@student.utwente.nl
Manuela Pluntke
Affiliation:
M.Pluntke@tnw.utwente.nl
Benjamin Cross
Affiliation:
benjamin.cross@grenoble.cnrs.fr
Jean-Christophe Baret
Affiliation:
jean-christophe.baret@philips.com
Frieder Mugele
Affiliation:
f.mugele@utwente.nl, Netherlands
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Abstract

We measured the electrowetting behavior of aqueous salt solutions. By varying the conductivity and the frequency of the applied AC voltage we determined the range of the validity perfect conductor assumption of the standard electrowetting theory for the case of AC voltage. We show that the contact angle reduction is dramatically reduced at high frequency and low salt concentration due to Ohmic losses with the liquid. A simple RC-equivalent circuit model explains the observations. It is demonstrated that finite conductivity effects are more pronounced for sessile droplets than for droplets confined between to parallel plates.

Keywords

electrical propertiesliquidfluidics
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 899: Symposium N – Dynamics in Small Confining Systems VIII , 2005 , 0899-N06-01
Copyright
Copyright © Materials Research Society 2006

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References

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