Coulombically driven rolling of nanorods on water.

We use molecular dynamics simulations to examine the possibility of rolling nanorods on the surfaces of polar liquids. Asymmetric charging of nanorod surfaces, generated by light excitation of its photoactive hydrophobic surfactants, can induce asymmetric Coulombic coupling to the polar liquid surfaces. We demonstrate that under this driving nanorods with diameters of 3-10 nm can roll on water with translational velocities of 1-5 nm/ns. The efficiency of this motion is controlled by the chemistry and dynamical phenomena at the nanorod-water interface.