On the mechanism of performance improvement of electroactive polyvinyl chloride (PVC) gel actuators via conductive fillers

The electromechanical actuation of transparent plasticized polyvinyl chloride (PVC) gels with conductive fillers were studied. The effects of functionalized carbon nanotubes (CNTs) and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF(4)) ionic liquid (IL) on both the electrical conduction and dielectric processes within PVC gels were investigated, and the differences between the two were clarified. Both CNTs and IL were shown to increase the conductivity of the gels and produce larger electromechanical transduction of a contraction actuator, but only CNTs were shown to increase the electrostatic adhesion force of the PVC gels. The addition of charge carriers to the gel via the inclusion of ILs was shown to significantly reduce the conductivity relaxation time, and the transient current upon voltage polarity reversal indicated multiple peaks corresponding to the introduction of carriers with different polarities and mobilities into the gel. This is believed to cause a screening effect, reducing the charge accumulation at the anode that is the foundational basis for PVC gels’ actuation mechanism. A recommendation for preferable conductive fillers for various applications is made.