Enhanced Electro-actuation in Dielectric Elastomers: The Nonlinear Effect of Free Ions

Plasticized poly(vinyl chloride) (PVC) is a jelly-like soft dielectric material that attracted substantial interest recently as a new type of electro-active polymers. Under electric fields of several hundred volt/mm, PVC gels undergo large deformations. These gels can be used as artificial muscles and other soft robotic devices, with striking deformation behavior that is quite different from conventional dielectric elastomers. Here, we present a simple model for the electro-activity of PVC gels and show a nonlinear effect of free ions on its dielectric behaviors. It is found that their particular deformation behavior is due to an electro-wetting effect and to a change in their interfacial tension. In addition, we derive analytical expressions for the surface tension as well as for the apparent dielectric constant of the gel. The theory indicates that the size of the mobile free ions has a crucial role in determining the electro-induced deformation, opening up the way to novel and innovative designs of electro-active gel actuators.

Automated summary

Plasticized poly(vinyl chloride) (PVC) gels exhibit large deformations under electric fields and can be used in artificial muscles and soft robotic devices. The size of mobile free ions plays a crucial role in determining electro-induced deformation. Theoretical analysis provides new insights for the design of electro-active gel actuators.