29-06-2010, 07:21 PM
Electrowetting
It s the modification of the wetting properties of a hydrophobic surface with an applied electric field. Gabriel Lippmann in 1875 explained the electrowetting behavior of mercury and other liquids.
Electrowetting theory
The formal definition of this effect is : "the change in solid-electrolyte contact angle due to an applied potential difference between the solid and the electrolyte" . the electrolyte droplet is pulled down onto the electrode by the fringing field at its corners thereby contact angle and increasing the droplet contact area. he energy stored in the capacitor formed between the conductor and the electrolyte adds to the Gibbs free energy raising it. the surface tension of an interface has an alternate definition that "it is the Gibbs free energy required to create a certain area of that surface". Thus when the Gibbs free energy surface tension changes accordingly.
This behaviour is better explained by the thermodynamic model. It gives a equation governing the the dependence of contact angle on the effective applied voltage as.
Materials
Only some surfaces show the theoretically predicted electrowetting behavior whose reasons are still being researched. Amorphous fluoropolymers form the best electrowetting materials. appropriate patterning can enhance their behaviour.
Applications
-adjustable lenses
-electronic displays
-modulab
-switches for optical fibers.
for full details , refer these:
http://en.wikipediawiki/Electrowetting
http://users.monash.edu.au/~lyeo/Dr_Lesl...uidics.pdf
http://doc.utwente.nl/54091/1/electrowetting.pdf
It s the modification of the wetting properties of a hydrophobic surface with an applied electric field. Gabriel Lippmann in 1875 explained the electrowetting behavior of mercury and other liquids.
Electrowetting theory
The formal definition of this effect is : "the change in solid-electrolyte contact angle due to an applied potential difference between the solid and the electrolyte" . the electrolyte droplet is pulled down onto the electrode by the fringing field at its corners thereby contact angle and increasing the droplet contact area. he energy stored in the capacitor formed between the conductor and the electrolyte adds to the Gibbs free energy raising it. the surface tension of an interface has an alternate definition that "it is the Gibbs free energy required to create a certain area of that surface". Thus when the Gibbs free energy surface tension changes accordingly.
This behaviour is better explained by the thermodynamic model. It gives a equation governing the the dependence of contact angle on the effective applied voltage as.
Materials
Only some surfaces show the theoretically predicted electrowetting behavior whose reasons are still being researched. Amorphous fluoropolymers form the best electrowetting materials. appropriate patterning can enhance their behaviour.
Applications
-adjustable lenses
-electronic displays
-modulab
-switches for optical fibers.
for full details , refer these:
http://en.wikipediawiki/Electrowetting
http://users.monash.edu.au/~lyeo/Dr_Lesl...uidics.pdf
http://doc.utwente.nl/54091/1/electrowetting.pdf