permittivity

The dielectric constant is an essential electrical parameter to the
achievable voltage-induced deformation of the dielectric
elastomer. This paper primarily focuses on the temperature
dependence of the dielectric constant (within the range of 173 K
to 373 K) for the most widely used acrylic dielectric
elastomer (VHB 4910). First the dielectric constant was investigated
experimentally with the broadband dielectric spectrometer
(BDS). Results showed that the dielectric constant first increased
with temperature up to a peak value and then dropped to a
relative small value. Then by analyzing the fitted curves, the Cole–Cole
dispersion equation was found better to characterize the
rising process before the peak values than the Debye dispersion

Dielectric elastomer (DE) is a kind of electroactive polymer material,
capable of large deformation up to 380%. However, under conservative
operating conditions, DE is susceptible to instability with a small
deformation due to various modes of failure, including electrical
breakdown, electromechanical instability (EMI), loss of tension and
rupture by stretch. This paper proposes a free energy model in the
thermodynamic system of DE involving thermoelastic strain energy,
electric energy and purely thermal contribution energy to obtain the
stability conditions of all failure modes. The numerical results
indicate that the increase in temperature can markedly contribute to
improving the entropy production, the actuation stress and the critical