Atomic Layer Etching Technique for 2D Titanium Carbide Soft Robotics

Due to its exceptional properties, transition metal carbide (Ti2C3Tx) has drawn significant interest, particularly for its tunable electrical conductivity, robust mechanical stability, and adaptable responsiveness. These features make it highly promising for soft robotics and sensing technology developments. Nevertheless, the effectiveness of TMC-based soft actuators is often compromised by uncontrollable surface terminations, such as hydroxyl (-OH) and fluoride (-F) which are introduced during the synthesis process. By altering these surface functional groups, Ti2C3Tx can be engineered to exhibit specific, desired characteristics, enhancing its suitability for particular applications.<br/>This study introduces an innovative methodology to manipulate the surface termination of Ti2C3Tx through plasma atomic layer etching (ALE) treatment, which is a precise method to remove thin layers of materials, atom by atom, using alternating chemical reactions in plasma. Various plasma ALE conditions were applied to Ti2C3Tx flakes, with resultant alterations in surface termination analyzed via X-ray Photoelectron Spectroscopy (XPS). Additionally, changes in structure were evaluated using X-ray Diffraction (XRD) and Raman Spectroscopy. Furthermore, Ti2C3Tx/cellulose/plasma (TMC-CNF-P) actuators were fabricated utilizing Ti2C3Tx with controlled surface terminations. Remarkably, the TMC-CNF-P actuator exhibited robust responses to Near-Infrared (NIR) light, showcasing potential applications in soft robotics and sensing. The mechanism of controlled surface terminations contributing to the multi-responsive actuator will also be discussed.