Graphene-based composite for dielectric elastomer actuator: A comprehensive review

Dielectric elastomer actuator composites (DEACs) are a class of electroactive polymers that are capable of changing shape or size once applied with an electric field. Such materials have found applications in artificial muscles, micro-robotics and micro air vehicles at industries. The dielectric behavior, mechanical properties, and electric breakdown strength are the main parameters for adjusting actuation behavior of DEACs. This review provides a brief introduction to the effect of 2-dimensional carbonic filler on the percolation threshold during the fabrication of these composites. The design process of graphene nanosheets (GNs) and their derivatives are described based on the filler structure: simple filler and complex filler. For each group, recent remarkable developments are illustrated and the technical issues demanding further improvement are discussed. In general, graphene-oxide (GO) and reduced-GO (rGO), as commutable GNs, numerous cases of use in DEACs have been reported where these materials were employed for controlling the reduction rate of dielectric breakdown strength, maintaining loss parameter (dielectric loss (epsilon '') and loss modulus (E '')), increasing electromechanical sensitively (beta=dielectric permittivity (epsilon') / elastic modulus) and improving the state of filler dispersion with interfacial engineering. The current review discusses the latest trends in research development in achieving such graphene-enabled enhancements. A systematic approach has been undertaken to highlight the advancements and challenges of graphene-based DEACs and the key research areas that need immediate attention. (C) 2019 Elsevier B.V. All rights reserved.