Microfluidic bypass for efficient passive regulation of droplet traffic at a junction

We propose a simple design for microfabricated junctions that allows an equal and regular distribution of droplets between the two outlets of a T junction. It relies on establishing a connection between the two outlets shortly after the junction to provide short-time memory to the device and induce perfect alternation in the choice of the outlet. We experimentally demonstrate the benefits of this simple passive device by a direct comparison to junctions without bypasses. (c) 2006 American Institute of Physics.