Size and frequency distributions for various droplet generation systems.

	Geometry and material	Continuous phase	Size/μm	Frequency/Hz
Water in oil	Channel array in silicon78	Kerosene with monolaurate	21	∼5300 (est.)
	T-Junction in acrylated urethane44	Decane, tetradecane, and hexadecane with Span 80	10 to 35	20 to 80
	T-Junction in PMMA45	High oleic sunflower oil	100 to 350	10 to 2500
	T-Junction in PDMS60	C14F12 with (C6F13)(CH2)2OH	7.5 nl (plug flow)	2
	Shear-focusing in PDMS52	Oleic acid	13 to 35 (satellites <100 nm)	15–100
Oil in water	Channel array in silicon78	Water with SDS	22.5	∼5300 (est.)
	Sheath flow in glass caplllary79	Water with SDS	2 to 200	100 to 10 000
Gas in liquid	Flow-focusing in PDMS83	Water with Tween 20	10 to 1000	>100 000
	Shear-focusing in PDMS86	Water with phospholipids	5 to 50	>1 000 000
Liquid in air	DEP on hydrophobic insulator62	Air	10 pl	∼8 (est.)
	EWOD on hydrophobic insulator32	Air	∼700 nl	∼1 (est.)