Water spiders and even some lizards can walk on fluids, but is there a possibility of rolling a nanorod on the surface of water? Yes, using the principles of Nature. Researchers from the University of Illinois at Chicago have proved by developing a model of such a nanorod rolling on water. Using molecular dynamics simulations, the scientists showed how nanorods with diameters of 3-10 nanometers could roll on water with translational velocities of up to 5 nanometers per nanosecond.
Researchers charged the nanorod’s surface with a light beam tilted with respect to the surface of the water to excite the nanorod’s chromophores of molecules to absorb photons. Then the nanotube’s polarized chromophores become attracted to the water’s highly polar molecules, causing the nanorod to roll. By matching the time the light beam reaches the chromophores with the rotation speed of the nanorods, the researchers theoretically showed they should be able to keep the nanorod rolling at a steady pace.
Nanorod must couple well enough to the water surface to be propelled with minimal slipping, but not too much so that it ploughs deep pushing a lot of water to move.
The researchers also believe that the nanorod should be able to pull objects attached to it as it rolls on the water and this property could be used to transport nanoscale objects at the cellular level, which could be useful in biological applications, such as manipulation of large proteins, applications in sensing, or material preparation, to prepare tiny nets like fishing boats for novel types of applications.