Dual-responsive jumping actuators by light and humidity

Abstract

Development of a multiresponsive miniaturized soft robot that can jump in different scenarios is highly desirable. This requires the actuator to simultaneously realize a large bending angle, a fast response, and a high actuation force under multiple stimuli to overcome its own weight. The difficulty lies in matching the material mechanical properties, response capacity, and interfacial adhesion of the different responsive layers. In this work, by mimicking the makeup application process, we designed a synergistic actuator containing a photothermal expansion layer, an interfacial adhesion layer, and a moisture-responsive layer. Jumping actuation was achieved under near-infrared (NIR) light or moisture, where exceptionally high bending angle and bending speed were achieved when normalized to the thickness and temperature change. Inspired by frog jumping, direction-controlled jumping was realized by an asymmetric structural design. This work provides a new design strategy for miniaturized soft robots, sensors, and intelligent equipment.