Bio-inspired Soft Robot Driven by Transparent Artificial Muscle

Transparency is one of the few forms of camouflage used by natural creatures in a habitat with any backgrounds. Dielectric elastomer actuators (DEAs) have important applications in many areas such as soft robots, artificial muscles and compliant devices. However, conventional DEAs cannot mimic the transparent appearance of natural creatures by using conventional materials like carbon grease as the compliant electrodes since carbon grease is a viscous black fluid. In this work, transparent artificial muscles are demonstrated by exploiting blends of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) and waterborne polyurethane (WPU) as compliant electrodes. The PEDOT:PSS/WPU blends are conductive and transparent solids, and the dielectric elastomer actuator artificial muscles can achieve a voltage-induced area strain of 200% with a transmittance of higher than 88% over the entire visible light spectrum. A transparent soft robot driven by these transparent artificial muscles is demonstrated. The fully transparent robot can vibrate asymmetrically at specific frequencies and demonstrate translational motion while keeping camouflaged in colorful backgrounds. The finite element analysis and experiments reveal the working mechanisms of the robot consistently. The concept of transparent actuators and transparent soft robots can guide the design of next-generation soft robots.