Multiresponsive Ti3C2Tx MXene-Based Actuators Enabled by Dual-Mechanism Synergism for Soft Robotics.

Multiresponsive and high-performance flexible actuators with a simple configuration, high mechanical strength, and low-power consumption are highly desirable for soft robotics. Here, a novel mechanically robust and multiresponsive Ti3C2Tx MXene-based actuator with high actuation performance via dual-mechanism synergistic effect driven by the hygroexpansion of bacterial cellulose (BC) layer and the thermal expansion of biaxially oriented polypropylene (BOPP) layer is developed. The actuator is flexible and shows an ultrahigh tensile strength of 195 MPa. Unlike the conventional bimorph-structured actuators based on a single-mechanism, the actuator developed provides a favorable architecture for dual-mechanism synergism, resulting in exceptionally reversible actuation performance under electricity and near-infrared (NIR) light stimuli. Typically, the developed actuator can produce the largest bending angle (∼400°) at the lowest voltage (≤4 V) compared with that reported previously for single mechanism soft actuators. Furthermore, the actuator also can be driven by a NIR light at a 2 m distance, displaying an excellent long-distance photoresponsive property. Finally, various intriguing applications are demonstrated to show the great potential of the actuator for soft robotics.

One-Step Synthesis of Microdome Patterns for Microstructured Pressure Sensors with Ultra-High Sensing Performance.

Pressure sensors usually suffer from a trade-off between sensitivity and the linear sensing range, which may be improved by manipulating the geometric microstructure of active sensing materials via the molding strategy, standard photolithography technique, and so on. However, these conventional microengineering techniques require specialized equipment, which are extremely complicated, high-cost, and time-consuming to manufacture. Herein, a mold-free, scalable, low-cost, and environment-friendly one-step thermofoaming strategy is proposed to fabricate surface morphology-tunable microdome-patterned composites (MPCs). The microstructured pressure sensor is then prepared by coating the MPCs with highly conductive graphene. Remarkably, the as-prepared pressure sensor presents a better overall sensing performance compared to the previous pressure sensors prepared using complicated microengineering methods. Moreover, an electromechanical response model and finite-element analysis are used to clarify the sensing mechanisms of the present microstructured pressure sensor. Furthermore, several successful application demonstrations are conducted under various pressure levels. Considering the advantages of the one-step fabrication strategy over conventional surface microengineering techniques and the high performance of the microstructured pressure sensor, the present pressure sensor has promising potential applications in health monitoring, tactile sensation, wearable devices, etc.