Digital Light Processing 3D-Printed Multilayer Dielectric Elastomer Actuator for Vibrotactile Device

Dielectric elastomer actuators (DEAs) have emerged as promising components in the field of soft robotics. Multilayer DEAs can enhance the output performance compared to single-layer DEAs, but the common layer-by-layer stacking methods are time-consuming and likely susceptible to concerns about frequent dielectric breakdown. Herein, the one-piece multilayer DEAs are directly fabricated via the digital light processing (DLP) 3D printing method, taking advantage of the precise and intricate printed structure. The study also focuses on the adjustable DLP printable resin formulation, aiming to achieve a DLP printed polyurethane acrylate (PUA)-based dielectric elastomer (DE) material that exhibits desirable characteristics, such as an appropriate dielectric constant, modulus, and minimal hysteresis loss. The non-pre-stretch DLP-printed cylindrical DEA demonstrates a significant blocked force of 270 mN and maintains 45% actuation performance at a frequency of 100 Hz, attributed to both the printed multilayer structure and the optimized formulation of the DE material. Moreover, the feasibility of DLP-printed DEAs as vibrotactile devices is demonstrated. This work has advanced the development of rapid and efficient fabrication methods of multilayer DEAs using DLP printing, with enhanced force output and attractive applications in robotics and haptic interfaces.