Hao Yuan,Qingming Ma,Yang Song,Matthew Y. H. Tang,Yau Kei Chan,Ho Cheung Shum
In this study, Janus droplets are fabricated by inducing phase separation of single-phase droplets made up of an aqueous two-phase system (ATPS). The resultant Janus droplets are highly monodisperse in structures and internal morphologies. Due to the affinity partitioning properties of ATPS, encapsulated ingredients can automatically partition into different compartments of the resultant Janus droplets. The use of biocompatible and cytocompatible ATPS also enables the encapsulation of enzymes and cells in the resultant droplets with their activity preserved at a relatively high level.
Droplet-based microfluidics offers an effective approach for overcoming the drawbacks of high viscosity and costs of ionic liquids (ILs) in practical applications. However, studies on the hydrodynamic behavior of the formation of IL-based Janus microdroplets which can facilitate the multifunctional applications of ILs through unique structures, are still limited due to their complex interfacial properties and high viscosities. Here, magnetic ionic liquid (MIL)-water Janus droplets were generated in an assembled co-flowing 3D-printed microchannel. Seven typical flow patterns of MIL-water Janus droplet generation were presented in a mountain-shaped flow pattern diagram, which was compared to the flow regime demarcations of MIL single-phase droplet formation. The scaling law of MIL-water Janus droplet size was analyzed to further reveal the breakup mechanism of biphasic dispersed phases with large differences in viscosities and interfacial tensions. Besides, the morphology control of surfactant-free MIL-water Janus droplet in the microchannel was investigated qualitatively and quantitatively. And, by changing the continuous phase, the morphology evolution of MIL-water Janus droplet to core-shell structure was also observed. The present study would be useful for providing a deep and comprehensive understanding on the formation and structure control of IL-based Janus microdroplets which are promising candidates for the use in applications of catalysis and extraction.
危险品化学品经营许可证（带存储）