Bacterial Cellulose/MXene-Based Actuators via Dual-Mechanism Synergism of Light and Wet for Remote Control

Smart actuating materials are widely used as components in smart sensors, soft robotics, and other applications due to their responsiveness to external stimuli, such as heat, light, magnetism, and humidity. However, the preparation of multiresponsive materials remains a significant challenge. Herein, we report a multiresponsive MXene-based flexible actuator (MBC/PI). The actuator exhibits high actuation performance through a dual synergistic mechanism involving the humidity-responsive expansion of the bacterial cellulose (BC)/MXene composite layer (MBC) and the thermally induced expansion of polyethylenimine (PI). In the MBC layer, MXene acts as the skeleton, while bacterial cellulose acts as an enhancer, tightly bound through dopamine modification. Upon near-infrared (NIR) irradiation, the photothermal effect of MXene rapidly converts light energy into heat, triggering localized water evaporation and subsequent contraction in the MBC layer. Concurrently, the PI substrate undergoes significant thermal expansion due to its high coefficient of thermal expansion (CTE). This dual-response mechanism enables the actuator to demonstrate a remarkable reversible actuation performance under near-infrared (NIR) light stimulation. In a humid environment, the maximum bending angle of the actuator can reach 170°, and a 60° bending deformation can be achieved in just 2 s. This work proposes a strategy for constructing infrared-driven actuators and provides ideas for further development of multiresponsive actuators and other intelligent materials.