Electro-coalescence in step emulsification: dynamics and applications
Related Experiment Video
Updated: Dec 31, 2025

Glass-Based Devices to Generate Drops and Emulsions
Published on: April 5, 2022
Xing Huang1, Binbin He2, Zhongbin Xu2
1Institute of Process Equipment, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, China. xuzhongbin@zju.edu.cn and John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Abstract:
Step emulsification is a low-shear method to produce monodispersed microdroplets by spontaneous breakup of dispersed fluid at a spatial "step". As a semi-open microfluidic system, controllable coalescence of multiple components in step emulsification has not been achieved. Here, we use a low voltage to control the coalescence position of flow tips in the terrace. By investigating the interaction between the coalescence behavior and the hydrodynamics of the drop formation, we numerically predict the shape evolution of the flow tips and give a semi-empirical model to calculate the sizes of droplets by the flow rates and the voltage. Furthermore, we explore the capabilities of the electro-coalescer based on step emulsification. To trigger the coalescence in the wide reservoir, the clogging problem in precipitate-producing reactions is avoided. Besides, the low-shear nature of step emulsification also facilitates the production of multilayered droplets.
Related Concept Videos
Colloidal precipitates
Capillary Electrophoresis: Applications
Capillary zone electrophoresis (CZE) separates ionic components based on their electrophoretic mobility. It has been used to separate proteins, amino acids,...
Coagulation
Colloids
Electrophoresis: Overview
There...
Colloids and Suspensions

