Formation of viscoelastic droplets in a step-emulsification microdevice

In this article, polyethylene oxide glycerin aqueous solution is used as the dispersed phase, and cyclohexane is used as the continuous phase to study the formation mechanism of viscoelastic fluid droplets in a step-emulsification microdevice. The formation process of viscoelastic droplets mainly includes three stages: two-dimensional expansion stage, necking stage, and pinch-off stage. The elasticity has basically no effect on the two-dimensional expansion stage, but it can delay the process of the necking stage and cause the beading phenomenon of droplets in the pinch-off stage. The results show that the effect of elasticity on the droplet size is weak, but it cannot be ignored. Moreover, the elasticity will be coupled with the viscous force to reduce the operating range of the dripping regime. Finally, the influence of the elasticity on the formation of satellite droplets is analyzed, and the method to prevent the influence of satellite droplets is proposed.

Automated summary

This article investigates the formation mechanism of viscoelastic fluid droplets in a step-emulsification microdevice using polyethylene oxide glycerin aqueous solution as the dispersed phase and cyclohexane as the continuous phase. It is found that elasticity has a delaying effect on the necking and pinch-off stages of droplet formation, leading to the beading phenomenon.