We studied the detailed electrochemical and electromechanical properties of a polyvinyl chloride (PVC) gel with dibutyladipate (DBA) as a plasticizer and developed an electromechanical model based on the electrochemical data. We evaluated the electric deformation of the PVC gel by the bending displacement response of the PVC gel strip when a square-wave voltage is applied. We studied the electrochemical impedance measurements of the PVC gel under bias voltages. Based on the above electromechanical and electrochemical experimental results, we developed a deformation model of the PVC gel where the electric bending response is basically due to the electrochemical formation of the plasticizer-rich layer and its deformation from the Maxwell stress. Then, in order to enhance the actuation performance of polyvinyl chloride (PVC) gel actuators, we prepared PVC gel film with ionic liquid (IL) additives and studied the generated strain of PVC gel actuators with four types of ILs. We found that the actuator response of the PVC gels with 0.01 wt% ILs is almost two times larger than those without ILs at low applied voltages of 200 V to 600 V. We studied the electrochemical properties of the PVC gels with ILs and proposed an electromechanical model previously. On the basis of the proposed electromechanical model, the effect of IL additives on enhancing the actuation performance can be clearly described.
The plasticized polyvinyl chloride (PVC) gel-based soft actuator exhibits a fast response in air, large deformation, and low power consumption under an electrical field, so it shows great potential for use as a new type of soft actuator. In our previous study, we have developed a multilayered expansion and contraction-type actuator using PVC gel and stainless mesh electrodes. However, the actuator using rigid metal electrodes bring challenges of a notable weight and size, a limitation in flexibility and performance. In this study, to develop an actuator with higher performance and flexibility, we proposed a novel sheet actuator using PVC gel and flexible electrodes. We explain the driving mechanism of the proposed sheet actuator and investigate the basic characteristics of the actuators with different content of plasticizer and membrane thickness. Besides, we conducted a comparison experiment between the proposed PVC gel sheet actuator and the traditional dielectric elastomer actuator, founding that, the PVC gel sheet actuator had a positive potential to be driven at a lower DC field to get a bigger deformation and a faster response than those of the traditional dielectric elastomer actuator. And we discussed the difference between the two types of actuators with a theoretical model, finding a good agreement with the experimental results.
Soft actuators based on polymers are expected to be used for power sources to drive wearable robots which required in a wide range of fields such as medical, care and welfare, because they are light weight, flexible and quiet. Plasticized PVC gel which has a large deformation by applying a voltage and high driving stability in the atmosphere is considered as a suitable candidate material for development of soft actuator. Then, we proposed two kinds of novel flexible actuators constructed like yarn and textile by using plasticized PVC gel to develop soft actuator to realize a higher flexibility and low-voltage driving. In this study, we prepared prototypes of these actuators and clarify their characteristic. In addition, we considered the deformation model from its characteristics and geometric calculation. When a voltage was applied to their actuators, textile type actuator was contracted, while the twisted yarn type actuator was expanded. The deformation behavior of the proposed actuators could be found at a low voltage of 200V, the contraction strain of the textile actuator was about 27 %, and the expanding ratio of the yarn actuator was 0.4 %. Maximum contraction strain of textile actuator and expansion ratio of yarn actuator was 53% and 1.4% at 600 V, respectively. The calculation results from the proposed model were in roughly agreement with the experimental values. It indicated that deformation behavior of these actuators could estimate from models.