Non-monotonic electromechanical deformation of dielectric elastomer actuators with different surface densities of carbon nanotubes

This paper investigates the influence of CNTs (carbon nanotubes) surface density on the electromechanical actuation of dielectric elastomer (DE) actuators. A filter transfer technique is utilized to deposit CNTs electrodes on VHB (Very-High-Bond) 4905 elastomers with different surface densities. The electromechanical characteristics of VHB 4905 elastomers with different surface densities of CNTs electrodes are evaluated experimentally. Theoretical models are simultaneously established to analyze with experimental measurements. It is found that increasing the CNTs surface density may alter the dielectric constant and modulus of DE actuators which results in a non-monotonic varying behavior of the electromechanical deformation under DC voltages. Furthermore, the stability and repeatability of the CNTs electrodes under AC voltage are verified by conducting additional experiments under different frequencies. This research can be used to determine the CNTs surface density to optimize the electromechanical actuation of DE actuators.