An Effective Capillary Valve Based on Micro-hole Array for Microfluidic Systems.

Abstract

With the development of microfluidic systems for portable devices where the capillary force as the driving force drove the liquid in a microchannel. An effective capillary microvalve based on a micro-hole array is proposed in this paper for the purpose of good performance, and programmable control, and easy-to-fabricate. The Wenzel model was used to slow down the velocity of fluid flow. The microvalve was made by a hot-embossing and hot-bonding process. The valve function was assessed by liquid flowing experiments. The results showed that the valve employs an abruptly changing contact angle to slow down the fluid flow. The controlling time is approximately 177 - 213 s. The best control effect was obtained when the contact angle equaled to 90°. The effect of the roughness of the microvalve was also evaluated. Therefore, this work has a great potential and broad prospect for both research and applications in microfluidic systems, such as the portable devices in the medical testing field.