• Haiwang Li Haiwang Li
  • Teck Neng Wong Teck Neng Wong
  • Nam-Trung Nguyen Nam-Trung Nguyen

This paper presents theoretical and experimental investigations on valveless microfluidic switch using the coupled effect of hydrodymics and electroosmosis. Switching of a non-conducting fluid stream is demonstrated. The first part of the investigation focused on flow switching of a non-conducting fluid, while the second part focused on switching of aqueous liquid droplets in a continuous oil stream. Two sheath streams (aqueous Cl and glycerol) and a sample stream (silicon oil) are introduced by syringe pumps to flow side by side in a straight rectangular microchannel. Exterl electric fields are applied on the two sheath streams. The switching process using electroosmotic effect for different flow rate and viscosity of sample stream is investigated. The results indicate that the switching response time is affected by the electric fields, flow rate, and viscosity of the sample. At constant inlet volumetric flow rates, the sample streams or droplets can be delivered to the desired outlet ports using applied voltages.