Acoustic vaporization of single droplets

Abstract

It has been observed in the past that droplets in emulsions can be vaporized into gas bubbles by the application of acoustic tone bursts. This paper will show the vaporization of single albumin stabilized droplets as they are exposed to single acoustic tone bursts. An optical microscope was used to monitor single droplets in a flow tube (200 μm diameter). The flow tube was mounted in a small water tank with degassed and heated water (37<th>°C). A single-element focused transducer with a center frequency of 10 MHz was aimed at the intersect of the tube and the optical beam. A highly dilute droplet emulsion was injected into the flow tube and a special syringe setup was used to move the fluid column in the flow tube back and forth to position individual droplets in the volume of interest. A single sinusoidal tone burst (33 cycles at 10 MHz) was sufficient to transition single droplets in the range from 5 to 15 μm diameter. The formation of the corresponding gas bubbles was monitored and measured in the range of 30 to 90 μm. [Work supported by PHS Grant No. R01HL54201 and US Army Grant No. DAMD17-00-1-0344.]