Electromechanical deformation of conical dielectric elastomer actuator with hydrogel electrodes

Abstract

A conical Dielectric Elastomer Actuator (DEA) undergoes large actuation strain in longitudinal direction when subject to a voltage across the membrane. The conical DEA is modeled using continuum mechanics and multilayered material thermodynamic theories which can consider not only the inhomogeneous deformation of the DEA but also the effect of elastomeric electrodes on the DEA. Hydrogels with lithium chloride electrolyte are synthesized and introduced as electrodes. The theory coincides well with the experimental results and succeeds in predicting the occurrence of loss of tension. At a low level of pre-stretch λp=2, electric breakdown always occurs before the loss of tension, independent of shear modulus of hydrogels. When the pre-stretch increases to 4, the dominating failure mode changes from electric breakdown to loss of tension. At μGEL=6 kPa, loss of tension and electric breakdown almost happen simultaneously and the maximum actuation strain occurs at λp=4.