Table 3.

Typical advantages and disadvantages of different major actuation methods used in PMPs.

Actuation method	Advantages	Disadvantages
Electrostatic	Fast response	High operating voltage
	Simple-to-control stroke	Small stroke
	Low power consumption	Electrolysis (for polar working fluids)
	Planar structure
	Small footprint and size
Motor	Low operating voltage	Complex external mechanism for handling rotary motion
	Large stroke	Non-planar structure
	Peristalsis-friendly	Relatively large
	Flexibility to couple to various transmission mechanisms
Piezoelectric	Large actuation force	High operating voltage
	Fast response	Small stroke
	Simple structure	Complex and bulky driving circuit
	Planar structure
Pneumatic	Large stroke	Slow response
	Simple-to-control actuation force	Non-planar structure
	Small footprint	External compressed air and control valves required
	Soft-lithography-friendly	Not portable
Thermal (Thermopneumatic Phase-change Shape memory alloy Hydrogel)	Low operating voltage	Slow response
	Large stroke	High power consumption
	Large actuation force	Temperature elevation in working fluid
	Planar structure
	Small footprint and size
	Simple driving circuit