Real-time video shows the use of microfluidics, or the manipulation of fluids at the microscopic scale, to produce water droplets whose sizes are highly uniform and can be easily adjusted.
Descriptive text for visually impaired: Water flowing through a tiny channel enters a narrow constriction. The water is being pinched at the constriction by oil flowing parallel to the water. The water's abrupt pressure drop—accompanied by a dash of surfactant in the water—breaks its surface tension, splitting it into small droplets. The size of the droplets can be tuned by adjusting the amount of surfactant, the main component in detergent. The droplets in this video are made larger than they are in the experiment. They have a very small amount of surfactant and therefore coalesce immediately after being produced. In the experiments, individual drops, much smaller in size, are captured and transported away from the stream with laser light.
Credit: Carlos Lopez-Mariscal and Kristian Helmerson, NIST
