In this paper, the authors present a comprehensive review of ionic polymer-metal composites (IPMCs) covering their fundamentals, fabrication processes, characterization and applications. IPMCs are becoming increasingly popular among scholars, engineers and scientists due to their inherent properties of low activation voltage, large bending strain -that is, the transformation of electrical energy to mechanical energy -and properties to be used as a bidirectional material -that is, they can be used as actuators and sensors. Among the diversity of electroactive