High wet-strength, durable composite film with nacre-like structure for moisture-driven actuators

As an emerging two-dimensional nanomaterial, Ti3C2TX MXene exhibits promising applications in the fields of energy, electromagnetic shielding, sensors and actuators. However, the structural instability and vulnerability to oxidation of MXene limit its application in moisture self-driven actuator. In this work, a composite film of moisture actuator with a lamellar structure inspired by pearl was reported. The composite film consists of tannic acid-modified Mxene and bacterial cellulose (BC). The synergistic interaction between TA and MXene imparts MXene with toughness and oxidation resistance, whereas the introduction of high wet/dry strength BC imparts the composite film with high tensile strength (243.5 MPa for dry strength and 173.4 MPa for wet strength) and high fracture strain (7.4 %). In addition, the actuator is highly moisture sensitive with fast response (2.48 s) and high cycling stability (more than 100 cycles). The results provide a strategy for the development of moisture-driven soft actuators, and reveal the great promise of this moisture actuator for applications in soft bionic robots and flexible arms, solving the current shortcomings of poor durability and low strength of MXene-based actuators, establishing the foundation for a wider application of moisture actuator devices.