Construction and regulation of aqueous-based Cerberus droplets by vortex mixing

The emerging aqueous-based Cerberus emulsion droplets with multi-domains behave as an excellent platform to design cyto-mimetic compartmentalization for fabrication of anisotropic biomimetic materials and microreactors. However, the ultralow water/water interfacial tension impedes fabrication of aqueous Cerberus droplets in batch-scale and precisely topology regulation especially under lack of deep understanding of w/w interface properties.

Aqueous-based ternary phase diagram composed by salt, hydrophilic polymer and fluorocarbon compound is determined. Different emulsions employing the multiple aqueous solutions as internal phase and vegetable oil as continuous phase, are prepared by traditional vortex mixing based on the diagram. The construction mechanism of (W1 + W2 + W3)/O Cerberus droplets and relationship between droplet topology and the diagram are investigated.

Diverse categories of aqueous-based emulsions from single emulsions, Janus emulsions, to Cerberus emulsions are delicately controlled in the same system based on the diagram. Various morphologies of Cerberus droplets such as linear and fan-like configurations are obtained, although spreading coefficient based on interfacial tension indicates preference of onion-like configuration. The viscosity plays an unexpected role in the construction of Cerberus droplets due to highly sensitive water/water interfaces within the droplets. Moreover, an empirical equation is perfectly applied, which endows quantitative prediction and control of lobe volume ratio within Cerberus droplets.