Manipulation of Monodisperse Emulsions in Microchannels

The manipulation of monodisperse gel emulsions confined in a microfluidic channel network has been investigated. The objective was to understand the organization of monodisperse gel emulsions based on dispersed phase volume fraction and to manipulate them using both fixed and switchable channel geometries. A combination of experimental methods was employed to analyze quasi two-dimensional structural transitions and controlled droplet formation. Results showed that transitions between certain arrangements in an emulsion flowing through a channel are induced by varying channel geometry, exhibiting hysteretic behavior dependent on droplet size and volume fraction. Moreover, active manipulation of emulsion arrangements was achieved using a ferrofluid as the continuous phase, demonstrating that external magnetic fields can effectively induce droplet arrangement transitions. Analysis included in situ measurements of droplet-encapsulated fibrin networks, revealing that droplet velocity distribution significantly influences fibrin network aggregation. When droplets were held stationary, elastic recovery of the fibrin network structure was observed after controlled deformation. These findings contribute to the understanding of emulsion behavior in microfluidic systems, offering insights into potential applications in material science and biomedical engineering.