טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAltshuler Gennady
SubjectInduction of Wetting Properties by Acoustic Waves in
Microfluidic Devices
DepartmentDepartment of Chemical Engineering
Supervisor Dr. Ofer Manor
Full Thesis textFull thesis text - English Version


Abstract

Acoustic fields with frequencies in the ultrasonic range generated by applying the reverse piezoelectric effect upon a photolitographically patterned surface of a Lithium Niobate (LiNbO3) crystal was shown to activate liquids with infinitely small contact angle such as silicone oil to motion in various flow regimes dependent upon the height of the liquid film. The current work validates those findings for liquids with finite contact angle, namely, water augmented with Sodium Dodecyl Sulphate (SDS) surfactant to reduce the resistance to flow. By presenting a new dimensional analysis which compares the capillary and the convective contributions to the film dynamics, a new dimensionless number appears to be tightly related to the velocity of the three phase contact line. In practice, the values of the dimensionless number were altered by changing the surfactant concentration related to the contact angle and the surface tension and the applied voltage related to the surface wave amplitude, which were predicted by the dimensionless number to be the dominant factors influencing film dynamics. The advances in the ability to dynamically manipulate thin liquid films entails great promise for the field of microfluidic device design and fabrication. Furthermore, the successful use of aqueous solutions in the current work could contribute to various chemical and biological applications due to the ubiquity of water in those fields.