Figure 3. Different operational modes of the bubble-based microvalve under a flow rate of 10 μL/min withdrawn from the outlet of the main channel: (a) Operation in the fully open mode with equal flows of red and blue streams through the main channel, (b) Operation in the partially closed mode with the flow of red stream reduced to half, (c) Operation in the fully closed mode with no red stream flowing through the main channel, (d) Re-opening the microvalve to retain the flow of red stream through the main channel.

Scale bar is 500 μm. (e) The variations of the red fluid ratio with respect to number of steps rotated by the stepper motor, and the area covered by the bubble. The experiments are repeated at least 4 times and the error bars represent the standard deviations.