The effect of cycling on charge-storage, actuation and sensing behavior of a polypyrrole is studied, having
its application for an electroactive catheter in mind. It is shown that the electrochemical capacitance of a
polypyrrole film decreases by about 15 % over the course of 100 cycles, while the per cycle rate of this
decrease drops by 75 % between the first and the last ten cycles, implying that a steady-state value may
exist. The decrease in capacitance is shown to have a significant effect on actuation strain. In order to
achieve a more constant capacitance and more robust actuation performance, it is proposed to pre-cycle the
potential of the film to exhaust the effect of processes that contribute to the decrease in capacitance and
allow it to reach a more constant value. The ability of a polypyrrole film to generate currents corresponding
to applied external load during actuation is verified and the cycle life time of such a sensor is studied. It is
shown that after an initial decrease, the sensor current reaches a steady-state value as well, and maintains
that value at least over 5600 cycles.
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