Model of dissipative dielectric elastomers

Abstract

The interplay of the polyelectrolyte-surface electrostatic and non-electrostatic interactions in the polyelectrolytes adsorption onto two charged objects -A self-consistent field study J. Chem. Phys. 137, 104904 (2012) Voltage-induced deformation in dielectric J. Appl. Phys. 112, 033519 (2012) Concentration and mobility of charge carriers in thin polymers at high temperature determined by electrode polarization modeling J. Appl. Phys. 112, 013710 (2012) Crystal phase dependent photoluminescence of 6,13-pentacenequinone J. Appl. Phys. 112, 013512 (2012) Frequency-dependent dielectric response model for polyimide-poly(vinilydenefluoride) multilayered dielectrics Appl.The dynamic performance of dielectric elastomer transducers and their capability of electromechanical energy conversion are affected by dissipative processes, such as viscoelasticity, dielectric relaxation, and current leakage. This paper describes a method to construct a model of dissipative dielectric elastomers on the basis of nonequilibrium thermodynamics. We characterize the state of the dielectric elastomer with kinematic variables through which external loads do work, and internal variables that measure the progress of the dissipative processes. The method is illustrated with examples motivated by existing experiments of polyacrylate very-high-bond dielectric elastomers. This model predicts the dynamic response of the dielectric elastomer and the leakage current behavior. We show that current leakage can be significant under large deformation and for long durations. Furthermore, current leakage can result in significant hysteresis for dielectric elastomers under cyclic voltage.

Mechanics of dielectric elastomers: materials, structures, and devices

“…A DE-based device is often subjected to time-varying forces and voltages working as an actuator or a generator (Hong, 2011;Foo et al, 2012a;Hu and Suo, 2012;Zhang et al, 2014b). Therefore, the working performance of the DE device can be severely influenced by the undergoing dissipative process within the material.…”

“…The DE membrane recovers its original configuration when the voltage is removed; (c) An elastomer film at its reference state, with randomly distributed polymer dipoles; (d) Polarization of an ideal DE, in which the polymer dipoles are polarized freely; (e) A non-ideal DE under large deformation. The stress field is perpendicular to the direction of electric field, which impedes the polarization of dipoles (Anderson et al, 2012;Foo et al, 2012a) The nominal density of the Helmholtz free energy W generally depends on the mechanical and electric displacement as…”

“…Additionally, the dielectric relaxation is orders of magnitude faster than the viscoelastic relaxation, and as such the dynamic evolution of the dielectric relaxation is often ignored. Therefore, the entire dissipation process is approximated as solely the viscoelastic relaxation (Zhao et al, 2011;Foo et al, 2012a). At various working conditions, the viscoelasticity of a DE can remarkably influence its performance (Zhang et al, 2005;Plante and Dubowsky, 2006).…”

Dynamic Electromechanical Response of a Viscoelastic Dielectric Elastomer under Cycle Electric Loads

“…This rate-dependence is mainly induced by the viscoelasticity of the elastomeric polymer matrix and may consequently influence the electromechanical actuation [27]. Viscoelastic relaxation may be represented by a rheological model of springs and dashpots [34][35][36]. As the DE exhibits elastic deformation and inelastic deformation, the latter of which is time-dependent, we first model this material by assuming that it is composed of two molecular chain networks, A and B, as sketched in Figure 2.…”

“…Based on the theory of nonequilibrium thermodynamics [34][35][36] and the nonlinear vibration modeling [16][17][18][19], we aim to characterize the electromechanical and dynamic response of viscoelastic dielectric elastomer, to predict how viscoelasticity affect its dynamic performance and hysteresis process by comparing with the quasistatic response, and to present a physical interpretation on the instability and stability evolution coupled by viscoelasticity, relaxation time, and dynamic deformation.…”