Poly(3,4-ethylenedioxythiophene), or PEDOT, freestanding films were synthesized and characterized as conducting polymer linear actuators. Variations of solvent and electrolyte led to the observation of strains greater than 4% with maximum strain rates of 0.2%/s during electrochemical interrogation in an ionic liquid environment. The ionic liquid 1,3-butylmethylimidazolium hexafluorophosphate, BMIMPF6, enabled the largest strains to be observed repeatedly while the polymer was held at a stress of 1.0MPa over tens of cycles. The ionic liquid environment also produced a single polarity in the relationship between charge and strain. This single polarity suggested that only the imidazolium cation was actively intercalating into and out of the polymer film. The possible sources and consequences of such a mechanism as compared to actuation in conventional solvents and electrolytes which show dual polarity of charge and strain is discussed.
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