Table 1.

Active micromixers reported in recent five years.

Energy Source	Characteristic	Mixing Time (s)	Re	Mixing Efficiency	Reference
Electrical field	Conductive sidewall	0.033	<1	-	[21] b
	Ferrofluid flow	20	-	-	[23] c
	Circular copper electrodes	110	-	>90%	[20] b
	Asymmetric lateral structure	-	-	100% 2	[26] a
	Floating electrode	1.15	-	95% 3	[25] c
Pressure field	Pulse width modulation	-	83–125	90% 2	[15] a
	Braille Pin Actuator	0.5	4	90% 2	[14] b
	Rotary peristaltic micropump	1	-	90% 4	[7] c
	Single-chamber micropumps	0.45	0.03–30	92% 2	[16] a
Magnetic field	Permanent magnet	80	-	90% 2	[57] c
	Magnetohydrodynamic Actuation	-	0.12	81% 1	[47] a
	Rotating magnetic field	-	-	90–92% 2	[52] c
	Hybrid gradient magnetic field	8	-	97–99% 4	[48] a
	rotating magnetic microbeads	2.5–9	-	-	[54] c
Sound field	Bubble cavitation	0.100	0.01	92% 2	[38] b
	Vibrating membrane	0.003	-	90% 3	[6] c
	Bubbles	0.05	0.01	93% 2	[43] b
	Micro-pillars	6	-	-	[40] b
	Sharp-edges	0.18	-	-	[36] b

^a Research including only simulated results. ^b Research including only experimental results. ^c Research including both of simulated and experimental results. ¹ Mixing Index calculated based on Equation (1). ² Mixing Index calculated based on Equation (2). ³ Mixing Index calculated based on Equation (3). ⁴ Mixing Index calculated based on Equation (4).