Long-range hydrodynamic communication among synthetic self-propelled micromotors

Long-range communication is ubiquitous among living organisms, but it remains undiscovered among synthetic micro/nanomotors. Here, we report the long-range hydrodynamic communication among synthetic micromotors. With the high activities when powered by a mixed fuel of N2H4 and H2O2, catalytic micromotors move in a stable oblique head-down orientation and thus generate strong, steady converging phoretic flows near a substrate. Consequently, they can emit robust hydrodynamic signals to trigger neighboring motors within a long range and also initiate an "approach-hit-and-run'' response when sensing the signals emitted from others. This hydrodynamic communication can be reciprocal or one-way, intraspecific or interspecific, spontaneous or controllable, and it widely exists in various catalytic micromotor systems. Utilizing the hydrodynamic signal, the micromotor can also act as a leader to gather small particles (followers) and exhibit a biomimetic competitive behavior against others for the followers. This work may facilitate the fabrication of intelligent micro/nanorobots for micro-manipulations and biomimetic micro/nanorobotic systems.