Easy droplet generation chip

How does generation of monodisperse droplets work? 

Droplet generation in a microfluidic chip can be achieved using different geometries. With the EZ Drop droplet generation chip, a flow-focusing design is used. A channel brings the dispersed phase (water) towards an intersection, where 2 lateral channels, perpendicular to the dispersed phase, supply the continuous phase (oil). The oil pinches the water on both sides, and the combined effects of viscous forces and surface tension result in the formation of a droplet. 
This geometry allows the generation of highly monodisperse droplets with a large range of particle sizes and production frequency. 

Various production regimes can be achieved using this geometry, allowing for more or less stable emulsions and specific droplet sizes: 

• The dripping regime allows for generation of very monodisperse droplets with a diameter in the range of the channel’s width. In this case, the viscous shear forces dominate the droplet formation process. 
• The jetting regime results in detachment of the droplet, not at the intersection, but later in the collection channel. In this case, the generated drops can be much smaller but are usually less monodisperse. Emulsions are more difficult to control and keep stable. 

These 2 main droplet regimes can be obtained by changing the flow-rate ratio between the continuous phase and the disperse phase.