Photothermal actuator based on Nb4C3Tx@CNF composite for bionic applications and wireless cargo transportation

Abstract

Continuous breakthroughs in the field of smart materials have injected strong momentum into the development of flexible actuators. MXenes as an emerging two-dimensional transition metal carbide/nitride material shows an attractive application prospect in the field of flexible actuators. In order to expand the application of MXenes materials in the field of photothermal actuators, a novel photothermal actuator based on a composite of Nb₄C₃T_x material and cellulose nanofibers (CNF) was designed in this work. The difference in coefficient of thermal expansion (CTE) between the Nb₄C₃T_x@CNF layer and the polyimide (PI) layer of this actuator enables efficient light-driven bending deformations (bending curvature up to 0.95 cm⁻¹ and stable performance after 300 cycles). The actuator also exhibits Marangoni effect driving capability for high-speed (33.6 mm s⁻¹) and controlled complex motions (e.g., cargo sailing, obstacle avoidance) on the water surface. To validate the application potential of Nb₄C₃T_x@CNF/PI, the study further designed and demonstrated a variety of prototypes, including a bionic worm robot, a bionic human muscle, an intelligent four-finger gripping device, and a miniature cargo ship model. These applications fully demonstrate the versatility and practical value of Nb₄C₃T_x@CNF/PI in the field of flexible actuation. This work not only expands the application scope of MXenes in light-driven actuation, but also provides new ideas and important references for designing high-performance and multifunctional flexible actuators.