Strain dynamics under DC voltage of PEDOT:PSS-based microactuators

International audienceConducting polymer actuators exhibit large strain in response to an external stimulation, thus representing promise materials for MEMS. Presented as a trilayer structure composed of an ion reservoir membrane sandwiched between two electronically conducting polymers (ECP) as electrodes, the actuator exhibits bending deformation as a result of ions movements between the two electrodes during their redox process. We recently reported on the development of microactuators based on PEDOT:PSS, a commercially available ECP. Although microactuators are very often characterized by applying an AC voltage, many applications require subjecting the actuators to a DC voltage for several seconds or minutes. Some of these applications are the closing of a micro-gripper and the actuation of a cochlear implant during a surgery. With the aim of developing a micro-gripper, the dynamics strain of PEDOT:PSS-based trilayer micro-actuators have been studied by applying DC voltages in order to reach the maximum strain and force. The application of a DC voltage for an extended time shows that the actuator does not go back to its initial position after switching off the power supply. This study reveals the appearance of a memory effect, which is directlyrelated to the intrinsic operation of the ECP-based actuator. These results allow a better understanding of the actuation process and are needful for the modelling and future control of integrated ECP actuators in microsystems devices