Study on droplet formation with surface tension for electrohydrodynamic inkjet nozzle

Droplet ejection from an electrohydrodynamic (EHD) inkjet nozzle depends on many factors such as an onset voltage, liquid conductivity, surface tension, etc. Since the surface tension has an influence on the contact angle between the nozzle surface and the liquid droplet, the surface tension change should be investigated for the control of the droplet ejection. In this study, surfactant, which can weaken the surface tension force, was used to analyze the effect of the surface tension. Furthermore, hydrophobic coating of the nozzle surface was considered as another factor for the droplet ejection. Also, a flow visualization technique was developed to observe the droplet formation and ejection from the EHD inkjet nozzle by various surface tension values.