Microdroplet generation using an ultrasonic torsional transducer which has a micropore with a tapered nozzle

A generation of monodisperse droplets in various liquids is an important subject. In this study, we have generated droplets by using an ultrasonic torsional transducer and the micropore plate. Firstly, we have evaluated an effect of the micropore shape to droplet generation. The diameter of the micropore and the flection angle of the tapered nozzle are \(50 \, \upmu \hbox {m}\) and \(25^{\circ }\), respectively. The micropore with a tapered nozzle prevented liquid from spreading on the micropore. Therefore, the micropore with a tapered nozzle generates liquid column. In addition, we have generated droplets in the air by using pure water and various viscosity silicone oils and evaluated the generated droplets. The uniform size droplets of various liquids were generated when the ultrasonic torsional transducer and the micropore plate vibrate in torsional direction. We have evaluated the relationship between the diameter and some values which affect droplet formation. The diameter of droplet is decided by the applied pressure, the resonance frequency and the diameter of liquid column.