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Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain
and a moderate stress at low applied voltages (<5V). Bending actuators have limited engineering applications due to the
low forcing capabilities and the need for complicated external devices to convert the bending action into rotating or
linear motion desired in most devices. Recently Akle and Leo reported extensional actuation in ionic polymer
transducers. In this study, extensional IPTs are characterized as a function of transducer architecture. In this study 2
actuators are built and there extensional displacement response is characterized. The transducers have similar electrodes
while the middle membrane in the first is a Nafion / ionic liquid and an aluminum oxide - ionic liquid in the second. The
first transducer is characterized for constant current input, voltage step input, and sweep voltage input. The model
prediction is in agreement in both shape and magnitude for the constant current experiment. The values of α and β used
are within the range of values reported in Akle and Leo. Both experiments and model demonstrate that there is a
preferred direction of applying the potential so that the transducer will exhibit large deformations. In step response the
model well predicted the negative potential and the early part of the step in the positive potential and failed to predict the
displacement after approximately 180s has elapsed. The model well predicted the sweep response, and the observed 1st
harmonic in the displacement further confirmed the existence of a quadratic in the charge response. Finally the
aluminum oxide based transducer is characterized for a step response and compared to the Nafion based transducer. The
second actuator demonstrated electromechanical extensional response faster than that in the Nafion based transducer.
The Aluminum oxide based transducer is expected to provide larger forces and hence larger energy density.
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