Modeling the constraint effects of compliant electrodes in dielectric elastomers under uniaxial loading

Abstract

Dielectric elastomers are composite thin film structures composed of a dielectric polymer between compliant electrodes. Previous hyperelastic models have not modeled the constraint effects of compliant electrodes on the lateral contraction of the dielectric material as it stretches, and are therefore unable to fully describe the electromechanical behavior of the dielectric elastomer or provide a means to understand the constraint effects. An empirical boundary coefficient is introduced to model these constraint effects on the lateral boundaries of the material under uniaxial tension. Employing an averaged stretch ratio concept, it is shown that this coefficient can be obtained from experimentally measurable geometric variables. Values for the boundary coefficients of sample dielectric elastomer films were obtained from experiments performed on a uniaxial test stand. Incorporating the boundary coefficient into the model formulation, a specific hyperelastic stress–strain relation is derived to describe the electromechanical behavior of dielectric elastomers under combined uniaxial tension and electrical loading. Comparison of the experimental and predicted values of the induced force in the axial direction due to the Maxwell stress based on the uniaxial model shows favorable agreement.

Retracted: A concise review on the elastomeric behavior of electroactive polymer materials

“…For example, Lei and colleagues created CuS microspheres with PPy uniformly inserted into intertwined layered subunits and coated on the surface of CuS. It has a 227 F/g unique capacitance and strong circulation stability 5, 11, 12, 157–276 . Metal sulfides have excellent electrochemical capacitance and can ensure their pseudo‐capacitance due to the double‐layer charge storage of MoS 2 and the oxidation state of Mo in the range of +2 to +6.…”

“…These filers are also temperature‐dependent, thus would reduce the dielectric actuators elastic DAE application limit. The problems were partly solved by the coating of BT particles with a thin layer of polydopamine, 5, 10–12, 115–246 which improves its dielectric permittivity and reduces dielectric loss.…”

“…However, some attempts have been made to use conductive polymers as electrode materials for supercapacitors, such as PANI/PPy, PANI/PEDOT, or PPy/PEDOT composite materials. The structural characteristics and electrochemical activity of each component can be completely mirrored by rationally designing the integrated intelligent architecture of this composite material, and it has a nice synergy effect, thus increasing the capacitance performance of the composite electrode material 5, 11, 12, 160–278 . The PEDOT/PPy composite electrode prepared by electro‐polymerization, for example, has a high specific capacitance of 200 F/g and excellent cycle stability 161 .…”