Sound-Controlled Rotary Driving of a Single Nanowire

The acoustic manipulation has the merits such as no selectivity to manipulated objects, less heat damage to biological samples (for some principles), simple and compact structure, and light weight. We demonstrate a strategy to ultrasonically rotate a single nanowire in a water film on a substrate surface. Controlled mobile acoustic streaming field generated by the ultrasound around a vibrating fiberglass is used to rotate the nanowire at any position on the substrate surface. The nanowire center or end moves to the location directly under the vibrating fiberglass tip due to the acoustic streaming field, and serves as the rotation center. The driving torque has an order of magnitude of 10^-20 N·m. Stable angular speed of a rotating nanowire can be up to several radians per second, and the temperature rise at the manipulation spot is less than 0.1 °C. The method has potential applications in the assembling of micro/nanostructures, orientation of biological samples, and measurement of dynamics properties of micro/nanoentities.