A Microinjector Free of Satellite Drops and Characterization of the Ejected Droplets

This paper presents the droplet characteristics of a newly developed thermally driven microinjector, which uses asymmetric bubbles to increase the injection frequency significantly. Through special heater and chamber design, bubbles are generated to surround the nozzle in such a way to cut off the droplet tail and eliminate satellite droplets. Visualization systems are developed to verify the droplet ejection free of satellite droplets and to characterize the ejection and trajectory. A simple Stokes-flow model is also used to estimate the droplet ejection trajectory.