Study of droplet manipulation condition in droplet manipulation device using ultrasonic vibration

In this study, we have fabricated a droplet manipulation device which has a microchannel oscillated by piezoelectric actuator. This device can manipulate droplets by producing a pressure distribution of a standing acoustic field caused by ultrasonic vibration in the microchannel. The manipulated droplet's size has been estimated from the relationship between acoustic force and viscous force. The device has been designed by using a finite element method analysis. Fabricated device has been evaluated by observing droplets in manipulation experiment and measuring a manipulated droplet's distribution. When n-dodecane was used as dispersed phase, this device can manipulate a droplet whose diameter is larger than 20μm when the applied voltage and the driving frequency were 80Vp-p and 2.25MHz. When Silicone oil was used as dispersed phase, the manipulated droplets diameter was larger than 15μm. From these results, we have indicated that the microchannel device can manipulate droplets by using ultrasonic vibration. © 2016 The Institute of Electrical Engineers of Japan.