Impact of viscoelastic properties on bucky-gel actuator performance

Abstract

Due to their soft polymeric backbone and metal-free compositions, bending electromechanically active bucky-gel laminates are attractive candidates for actuators in applications in a variety of fields such as medicine and space technology. However, the soft structure of these materials also proposes challenges to engineering new devices as the unorthodox composition requires that the developer really understands the mechanical nature of these actuators. As the composition of bucky-gel laminates includes porous polymer filled with ionic liquid but also carbon nanotubes, the viscoelastic nature and how it possibly affects actuator performance is of great interest. Several customised mechanical tests are implemented on both electrically active and inactive bending bucky-gel actuators to investigate their mechanical properties. It is reported that these materials are highly viscoelastic and their mechanical relaxation can be described by generalised Maxwell model for solids. Moreover, these viscoelastic effects are shown to depend on the level of input voltage, thus, altering the overall performance of the actuator. Temperature measurements reveal remarkable thermal dissipation during the actuation cycles, which, as the dynamic measurements demonstrate, alters the mechanical properties of bucky-gel actuators.