Droplet Printing Enabled by Cavity Collapse Ejection.

The behavior of cavity collapse in liquids is of fundamental importance in natural and industrial applications. It is still challenging to use the phenomenon of cavity collapse ejection in on-demand droplet printing technology. In this study, we investigate the cavity collapse ejection phenomenon in the submillimeter to millimeter scale and demonstrate that the cavity capillary energy is a critical factor affecting the state of the generated jet. Based on this phenomenon, we developed a droplet printing technology that can print nanoliter satellite-free droplets from a millimeter-sized nozzle, which reduces the risk of nozzle clogging. Using this printing technology, we demonstrated the printing of a nanoparticle suspension with 60% mass loading. Finally, we also showcased the printing of various inks for different applications using this technology, demonstrating the printability of cavity collapse-ejection printing technology in functional inks and showing potential to be applied in scenarios such as bioassays, the electronics industry, and additive manufacturing.