As the characteristic dimension of fluid flow is reduced
to the micrometer range, surface energy becomes an
increasingly important factor in determining the flow
behavior. Because the surface-to-volume ratio is inversely
proportional to the width of a channel, forces that arise
from surface tension will become comparable to the inertial
force of the fluid at a sufficiently small length scale. At
this point, it becomes possible to manipulate the motion
of the fluid or fluid droplet by modulating the surface
tension, which can be achieved with anumberof strategies,
including the use of light,1,2 temperature gradients,3,4
electric field,5-7 electrochemical methods,8 and direct
patterned surface modifications.9-11 For microfabricated
systems, the use of electric field to control dynamically
the wetting properties of the surface provides a particularly
versatile and convenient approach.12-15 By burying
metal electrodes underneath selected dielectric
materials,16-18 a circuit can be devised easily and rapidly
for manipulating fluid droplet movement using this
electrowetting effect.
Revised: February 2, 2005 |
Published: January 21, 2003
Citation
Kuo J.S., P. Spicar-Mihalic, I. Rodriguez, and D.T. Chiu. 2003.Electrowetting-Induced Droplet Movement in an Immiscible Medium.Langmuir 19, no. 2:250 -255.