Ionic Electro active Polymer-Based Soft Actuators and Their Applications in Microfluidic Micropumps, Microvalves, and Micromixers: A Review

This paper provides a detailed review on applications of ionic electroactive polymer (i-EAP) soft actuators as active elements of microfluidic micropumps, microvalves, and micromixers. The related works that have so far been presented by various research groups in the field have been collected in this review, which in the presented comparative procedure here shows the progress of this field during the time. Microfluidic technology as a pioneer field in bioengineering needs to have some active components likes pumps, valves, and mixers to obtain efficient functionality. Most of the conventional microfluidic active components are challenging to assemble and control outside the laboratory since they need some special facilities, which is not cost-effective. This is while some of the main targets of the microfluidic devices are for the development of point of care (POC) diagnostic systems, home usability, ubiquitousness, and low-cost ability. To solve these problems, i-EAPs have shown promising features to be the proper candidates as active elements of the microfluidic devices. Ionic polymer-metal composites (IPMCs), Conducting polymer actuators (CPAs), and Ionic carbon nanotube-based actuators (i-CNTAs) are three main types of the i-EAPs. In this paper, the working principles, fabrication, and microfluidic-based applications of these three categories are described in details. To have a proper comparison between all the reported i-EAP based microfluidic devices, several important features, i.e., applied voltage/frequency, device materials, electrode material, membrane material, and the main measured index of each device, have been reviewed.