A Soft Actuator With Controllable Deformation Driven by Humidity

The high flexibility and adaptability of the soft actuator have attracted wide attention. However, under the stimulation of the external environment, the complex and controllable movement of materials remain a challenge. In this work, we make a bilayer composite film simply and quickly by depositing silicone rubber (Ecoflex00-30) on the side of the plant parchment. It spontaneously controls deformation and responds sensitively in the water. This bilayer composite film exhibits a good stable actuation effect and reversibility in a humid environment or in water. We cut the strips of plant parchment into different fiber directions and control the lateral gradient in the thickness direction to achieve complex and controllable motion (bending, S-shaped, -shaped and spiral). Inspired by the plant tendrils, we design and built a soft gripper that can achieve 30 times its own weight in the water, demonstrating promising bioinspired applications.