One-to-one alternating droplet generation in a microfluidic double T-junction at low interfacial tension

Abstract

The one-to-one alternating droplet generation (OOAG) in a double microfluidic T-junction is a newly-developing method to construct droplet reactors. However, little attention was paid to its precise control, especially at low interfacial tension. This work filled in the gap through the experimental and theoretical exploration. Four fluid systems were adopted to make the research conclusions more general. The mechanism of flow-patten transition was analyzed to establish a predictive model describing the operation window of OOAG. Interface dynamics analysis suggested that independent of the proportion of continuous-phase, the droplet formation was suppressed and accelerated by the opposite dispersed phase at the earlier and later stages, respectively. Additionally, the opposite dispersed phase delayed the droplet breakup at low proportion of continuous phase through the interface deformation. A predictive model for droplet size was established by considering the mutual effect of the two dispersed phases and the fluid properties.