Leaf‐Inspired Programmable and Color‐Changing Moisture‐Responsive Actuator for Bionic Soft Robotics

ABSTRACT Mimicking the structures and behaviors of natural organisms is of great significance for scientists to develop novel smart devices for practical applications. However, the design and fabrication of bionic actuators with outstanding actuation performance and complex functionality remain challenging. Herein, we draw inspiration from natural leaves to design a stripe‐structured multifunctional actuator composed of Nafion, crystal violet (CV), and MXene@Fe 3 O 4 , which exhibits synergistic shape morphing and color transition in response to moisture stimulation. The programmable structural change capability of the actuator is uniquely achieved by constructing the vein‐like stripe patterns through a facile magnetic field‐assisted alignment method. The resultant moisture‐responsive actuator demonstrates exceptional performance, including a rapid response speed of 205.7°/s, and a large bending angle of 288°. This actuator also responds to changes in relative humidity by reversible protonation of CV with distinct color shifts. As a proof‐of‐concept, the actuators are used to create versatile smart devices and robots, such as biomimetic grippers, weightlifting robots, self‐sustained oscillation devices, soft crawling robots, smart mask, bionic hand, blooming flowers, artificial mimosa, and fluttering dragonfly. This study provides an elegant strategy for the design and fabrication of multi‐functional moisture‐responsive actuators for future bio‐inspired intelligent soft robotics.