(562h) Integration of 2D Materials with Soft Matter for Multifunctional Robotic Materials

Emerging soft robots with infinite degrees of freedom are one step closer to providing better human-machine interactions than conventional hard and stiff robots, attributing to their outstanding compliance/adaptability, distributed stress, and programmable actuating behaviors. Soft matter (e.g., hydrogels and elastomers) with high mechanical stability has been usually adopted for the fabrication of soft robots. However, soft matter exhibits limited optical, electrical, thermal, chemical properties that restrict the development of robotic functionalities. An emerging approach is to develop multifunctional robotic materials that are reconfigurable and can provide diverse built-in functions, such as wide-spectrum protection, tactile sensing, and wireless communication. To realize this approach, two-dimensional (2D) materials with diverse yet unique physicochemical properties have been recently integrated with soft matter to bring in add-on functionalities for the fabricated soft robots. In this presentation, I will highlight three integration approaches that have been realized by our group for the fabrication of 2D material-soft matter robotic materials: (i) heterogenous blending of 2D materials with soft matter dispersion followed by in situ crosslinking/curing; (ii) bilayer integration of textured 2D materials with soft matter substrate; (iii) post-stabilization of 2D material (or 2D material-templated) architectures with elastomer. The advantages and drawbacks of each approach regarding fabrication process and resulting characteristics will be discussed in detail. The as-fabricated 2D material-soft matter composites are then applied as multifunctional robotic materials, and their reversible actuating behaviors as well as built-in capabilities (e.g., wide-spectrum protection, tactile sensing, and wireless communication) are summarized. Finally, current research gaps and future directions regarding the development of multifunctional robotic materials across multiple length scales are addressed from our perspective by considering the design principles for future untethered soft robots.