Figure 5.

Droplet charging and sorting with different actuation voltages. (a) One-droplet sorting per two-droplet generation with the minimum actuation voltage of 120 V, the droplet generation frequency of ∼200 droplets∕s. (b) Minimum actuation voltage V_min to sort the droplets with respect to droplet size. For instance, a single droplet (25 μm, 8.3 pl) per two-droplet generation can be sorted up to the droplet generation frequency of 600 droplets∕s with a minimum actuation voltage of 88 V. (c) Unstable sorting with an applied voltage beyond a critical voltage of ∼160 V.