An ultrasonic manipulator with noncontact and contact-type nanowire trapping functions

• Noncontact and contact NW trapping functions can be integrated in one device.
• The design is based on the control of acoustic streaming field.
• Two different excitation modes are employed.

The ultrasonic manipulation technology had a breakthrough recently, which makes ultrasonic trapping, orientation, transportation, rotation and concentration of nanowires possible. However, the existing manipulation technology based on ultrasound cannot integrate the noncontact and contact nanowire trapping functions in one device. It would widen the application range if a manipulator has both the noncontact and contact trapping functions. In this work, we proposed and developed a dual function device capable of trapping individual nanowires in the noncontact and contact ways. The device is simply made up of a piezoelectric component, a vibration transmission needle, and a micro manipulating probe. The vibration transmission needle, made of steel, is bonded along the narrower side of the piezoelectric component to transmit vibration energy from the piezoelectric component to the manipulating probe. The micro manipulating probe, made of fiberglass, is bonded to the tip of the vibration transmission needle, to generate an acoustic streaming field to trap an individual nanowire in water film on a substrate. In the experiments, individual silver nanowires with a 300 nm-diameter and length up to 30 μm can be trapped and transferred in the contact and noncontact ways. The analyses show that making the micro manipulation probe oscillate linearly and elliptically at proper working frequencies is a way to integrate the noncontact and contact trapping functions in one device.