Fast-moving soft electronic fish

TLDR

Soft robots driven by stimuli‑responsive materials offer high adaptability for field exploration and human interaction, yet achieving self‑powered soft robots with high mobility, environmental tolerance, and long endurance remains a grand challenge. The design principle can be extended to a variety of flexible devices and soft robots. The fish is propelled solely by a soft electroactive structure composed of dielectric elastomer and ionically conductive hydrogel, eliminating the need for a motor. The authors demonstrate a self‑powered soft electronic fish that swims at 6.4 cm s⁻¹ (0.69 BL s⁻¹), surpasses previous untethered soft robotic fish, remains nearly transparent for stealth, operates consistently across temperatures, and can run for 3 h on a single charge while using surrounding water as ground.

Abstract

Soft robots driven by stimuli-responsive materials have unique advantages over conventional rigid robots, especially in their high adaptability for field exploration and seamless interaction with humans. The grand challenge lies in achieving self-powered soft robots with high mobility, environmental tolerance, and long endurance. We are able to advance a soft electronic fish with a fully integrated onboard system for power and remote control. Without any motor, the fish is driven solely by a soft electroactive structure made of dielectric elastomer and ionically conductive hydrogel. The electronic fish can swim at a speed of 6.4 cm/s (0.69 body length per second), which is much faster than previously reported untethered soft robotic fish driven by soft responsive materials. The fish shows consistent performance in a wide temperature range and permits stealth sailing due to its nearly transparent nature. Furthermore, the fish is robust, as it uses the surrounding water as the electric ground and can operate for 3 hours with one single charge. The design principle can be potentially extended to a variety of flexible devices and soft robots.