Universal rotation of nanowires in static uniform electric fields in viscous dielectric liquids

The wide utilization of nanomanipulation as a promising approach in microorganisms, nanoelectromechanical systems, and assembly of nanostructures remarks the importance of nanostructures' motion in electric fields. Here, we study the rotational dynamics of metallic and non-metallic nanowires (NWs) in a static uniform electric field in viscous dielectric liquids. For metallic NWs, it has been theoretically shown that the electric field-induced rotation is practically independent of the geometrical dimensions and the electrical properties of NWs. Our experimental results for suspended silver (Ag) NWs in microscope oil are perfectly in agreement with this model. However, in the case of TiO2 NWs, as an example of non-metallic NWs, we surprisingly observe the exact same electromechanical torque as metallic Ag NWs under the same experimental conditions. This is mainly explained by NWs' high aspect-ratio which allows one to ignore the non-axial component of the electric field inside the NWs. Therefore, all high-aspect-ratio metallic Ag and non-metallic TiO2 NWs demonstrate an identical rotational speed in the same dielectric liquid and electric field. This result can be used for the controllable alignment or synchronous rotation of an ensemble of different types of NWs for hybrid and advanced devices. Published by AIP Publishing.