Magnetically actuated rod-shaped nanoswimmers

Abstract

The idea of creating and controlling very small autonomous devices or nanorobots, which are able to move and operate at such very small scales looks like science fiction. However, this idea may not be that far, many nanoswimming devices are being developed and the challenges of the propulsion in liquid environments at low Reynolds conditions are being overcome. Here, two types of magnetic nanorod-shaped nanoswimmers are realized, one consists only on a nickel nanorod and the other is a nickel-polypyrrole bi-segment nanorod. These nanorods have been actuated using oscillating and rotating magnetic fields and two main types of propulsion mechanisms have been reported, surface walking and flexible undulatory propulsion. An effective control of their speed and direction has been demonstrated and high swimming velocities have been achieved (above 100 μm/s for Ni nanorods)