A comparative study of metal-free air-operated polypyrrole and PEDOT based trilayer actuators is presented. Actuators made of both pure and combined conducting polymers are considered. Trilayer bending actuators, synthesized in similar conditions, are characterized in terms of the structure, electrochemical and electro-chemo-mechanical properties. The characterization was carried out using two popular electrolytes: LiTFSI in propylene carbonate and a room-temperature ionic liquid EMIm TFSI. The results reveal that structure and actuation properties of the synthesized actuators depend on both the polymer chosen for the chemically synthesized electrode layer as well as the electrochemically synthesized working layer.

A large-scale effort was carried out to test the performance of seven types of ionic electroactive polymer (IEAP) actuators in space-hazardous environmental factors in laboratory conditions. The results substantiate that the IEAP materials are tolerant to long-term freezing and vacuum environments as well as ionizing Gamma-, X-ray and UV radiation at the levels corresponding to low Earth orbit (LEO) conditions. The main aim of this material behaviour investigation is to understand and predict device service time for prolonged exposure to space environment.

In situ electrochemical dilatometry was used to study, for the first time, the expansion behavior of a porous carbon electrode in a pure ionic liquid, 1-ethyl-3-methyl-imidazolium-tetrafluoroborate. For a single electrode, an applied potential of − 2 V and + 2 V against the potential of zero charge resulted in maximum strains of 1.8% and 0.5%, respectively. During cyclic voltammetry, the characteristic expansion behavior strongly depends on the scan rate, with increased scan rates leading to a decrease of the expansion. Chronoamperometry was used to determine the equilibrium specific capacitance and expansion. The obtained strain versus accumulated charge relationship can be fitted with a simple quadratic function. Cathodic and anodic expansion data collapse on one parabola when normalizing the surface charge by the ratio of ion volume and average pore size. There is also a transient spike in the height change when polarity is switched from positive to negative that is not observed when changing the potential from negative to positive indicating the size and the shape of the ion is influencing the expansion behavior