Effects of effective voltages, electrode types and stretching states on electrical properties and actuation characteristics of dielectric elastomer materials

Abstract

In this study, the electrical properties of DE materials were systematically tested, and the effects of different effective voltages, electrode types and stretching states on permittivity, dielectric loss, conductivity, capacitance and electrical efficiency were discussed. The frequency dependence of the electric dipole in the material is revealed from the microscopic point of view. Finally, based on the structure and volume incompressibility of the DE, the actuation coefficient of the DE is proposed to characterize its deformation effect. The results show that the permittivity of the DE is very sensitive at high frequency, especially for DE materials with carbon electrode and gold-carbon electrode. At the same effective voltage and gold electrode, the permittivity decreases with the increase of equal biaxial stretching. For the same stretching area, the permittivity of equal biaxial stretching is larger than that of unequal biaxial stretching. The DE with carbon electrode has the largest dielectric loss and is easy to be destroyed in engineering application, which needs further optimization. The dielectric loss decreases with the increase of equal biaxial stretching, which is mainly due to the decrease of orientation deviation between main chain and side chain in DE material. The electric efficiency at low frequency is generally higher than that at high frequency, and the highest electric efficiency can reach 99.64%. With the increase of frequency, the actuation deformation coefficient decreases rapidly. This work will further promote the development of DE materials used in soft robot, and provide a theoretical reference for the design of actuators and sensors.