Light-Driven Actuation Enabled by 2D Transition Metal Carbides

2D transitional metal carbides (MXene) have attracted attention for its unique properties such as adjustable electrical conductivity, high mechanical stability, and versatile responsiveness, offering a huge potential for advancing soft robotics and sensing. However, the performance of the MXene-based soft actuator is limited by uncontrollable surface terminations (-OH, -F, etc) induced in the synthesis process. Modifying these surface functional groups allows for customizing Ti2C3Tx to possess desired properties.<br/><br/>In this work, we propose an innovative approach to engineer the surface termination of Ti2C3Tx using plasma treatment. The Ti2C3Tx flakes were exposed to different plasma conditions, with the resulting change in surface termination characterized by X-ray Photoelectron Spectroscopy (XPS). The morphology of Ti2C3Tx is evaluated using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Furthermore, we fabricated Ti2C3Tx /cellulose actuators using Ti2C3Tx with controlled surface terminations. In addition, cellulose in the nanocrystal, nanofiber, and microfiber phases are utilized and compared to obtain the best actuation performance. We observe that our Ti2C3Tx /cellulose actuator demonstrates strong responses to light and moisture, which can be applied in soft robotics and sensing applications. The mechanism of controlled surface terminations contributing to the multi-responsive actuator will also be discussed.