STUDIES ON MICROFLUID FLOW CONTROLS BASED ON THE CONFIGURATION OF MICROCHANNEL

Microchannel is not only a channel for fluid flowing,but also a tool for microfluid flow control. By incorporating the characteristics and feature of the microchannel,microfluid driving,sampling,mixing, separating droplets formatting and controlling have been realized.In recent years,most studies have been focused on the application of surface effects to achieve microfluid control,as the surface-to-volume ratio is nearly millionfold increased in microchannel relative to that in macrochannel and the surface effects are greatly increased in microfluidic flows.However,only a few studies were carried out on controlling microfluid flows by using microchannel structural characteristics.In order to illuminate the fact that the microchannel configuration is also an effective way to control microfluid flow behavior,this paper discusses two aspects of flow control based on microchannel configuration.One is a special configuration of microchanels to be used as microvalve,the other is a special microchannel configuration to be used for formatting and controlling tiny droplets.And thus microchannel configuration is shown to be able to play an important part in microfluidic control.