Reconfigurable Collective Swimming of Biomimetic Nanocomposite Robots

Nature inspires diverse designs and locomotion strategies of untethered robots. Herein, we present lightweight yet strong nanocomposite robots inspired by human musculoskeletal systems for agile and magnetically organizable swimming at air-water interfaces. The nanocomposite robot consists of carbon nanotube yarn (CNTY) framework and magnetic polymer composite surrounding it, functioning as a bone and skeletal muscle. When a pulsed rotating magnetic field is induced underneath the robots, the nanocomposite robot swims with on-demand rectilinear translational motion or rotational motion according to magnetic frequency, achieving agile swimming velocity of up to 180 body lengths per second. In the manipulation of multiple robots, magnetic attraction provides soft jointed locomotion among the nanocomposite robots, enabling reconfigurable trimodal swimming: assembled rectilinear translational swimming, assembled rotational swimming, and fluctuating rotational swimming. Finally, we will discuss vorticity control of water and vortex-induced transportation of numerous cargos through the reconfigurable collective swimming of multiple nanocomposite robots.