Tunable electromechanical properties of double-layer stacked anisotropic dielectric elastomer actuators

The current reported anisotropic dielectric elastomer (DE) actuators have some potential limitations for widespread application, such as the inability to adjust the anisotropic direction, and the related relatively complicated fabrication process. In this work, we propose a method to realize tunable direction and magnitude of electromechanical deformation of DE membranes. Two sheets of unequal-biaxial prestretched VHB 4905 membranes are attached at different rotation angles, forming an anisotropic DE actuator (DEA) with utilization of carbon grease electrodes. Experimental results demonstrate that, the direction and magnitude of the voltage-induced displacement of DEs is adjustable by tuning the unequal-biaxial prestretch ratio and rotation angle. In addition, the dielectric constant and maximum displacement at breakdown of the anisotropic DEA are also related to the rotation angle. The designed anisotropic DEA realizes the diversity of electromechanical actuation in both the planar 2D and the spatial 3D structures, which can be utilized to help design the practical soft actuators.