Magic microfluidic T-junctions: Valving and bubbling

We develop and characterize a simple microfluidic component: a T-junction of two microfluidic channels conveying a gas and a liquid into the junction. It can either microvalve the two fluids or microbubble the gas with its functions switchable and controlled by the inlet pressure ratio of the two fluids. For the microvalving, it requires no actuating, moving and sealing components. Instead, the flow channels and the mechanisms of supplying the two fluids into them provide all these functions automatically. For microbubbling, it generates indistinguishable (monodispersed) bubbles steadily and stably with their size and generation frequency well-controlled.