In this study, we investigate the effect of enhancing electrical and ionic conductivity of PEDOT:PSS/PVDF/PEDOT:PSS tri-layer actuators on the speed of charging and of mechanical actuation. We treated the conducting polymer films with methanol, then doped the device with ionic liquid electrolyte. For both treated and untreated tri-layer samples, we measured electrical resistance along the length of the film, ionic resistance through the thickness of the structure, and performed cyclic voltammetry to determine volumetric capacitance and the characteristic time constants. We also measured the mechanical displacement-frequency response of the conducting polymer cantilever beams. Our results showed that methanol treatment increased electrical conductivity by 20x and ionic conductivity by 1.7x. This enhancement did not significantly change the cut-off frequencies of the device. However, at frequencies < 1 Hz, we observed less drop-off in displacement amplitude in the treated samples. For the geometries and conductivities used in this study, improving conductivity of PEDOT:PSS contributed to actuation at frequencies above the cut-off frequency. This may have applications for devices that need to actuate at high frequencies, but not necessarily at maximum strain, such as vibrotactile haptic displays.
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