Amphibious Soft Robots Based on Programmable Actuators Fabricated by Brushing Chinese Ink on Paper

Soft robots based on actuators that can work in both on-ground and on-water situations are environmentally adaptable and can accomplish tasks in complex environments. However, most current amphibious actuators need external stimuli to move on water and require complex preparation processes. Herein, amphibious Ink-paper/polyethylene programmable actuators and robots are proposed, which are fabricated by rapidly brushing Chinese ink on paper. The actuator can bend on the ground and move autonomously on the water. On one hand, the actuator shows a maximum bending curvature of 2.66 cm^-1 under near-infrared light, and the actuation performance can be programmed by ink concentration. Moreover, actuators with pen-brushed information can be shape-programmed for dynamic information display. On the other hand, the actuator can autonomously move on the water by using Chinese ink as Marangoni fuel. The maximum moving velocity is 4.73 cm s^-1. When the ink is saturated in the water, the actuator can further be driven by an infrared laser. Finally, three soft robots with diverse programmable amphibious motions are designed. Both the crawling/bending motion on the ground and autonomous linear/rotary movement on the water can be programmed by altering actuator structures. This research will provide new inspirations for next-generation amphibious actuators and soft robots.