Janus emulsions formed with organic solvents as inner phases

Organic solvents are used as oil phases to prepare oil in water Janus emulsions by one-step vortex mixing. The categories of organic solvents cover alkanes, cycloalkanes , aromatics, alcohols and esters. Micrograph images show the well-defined Janus morphology composed by organic solvents and the corresponding immiscible oils. Topologies of “snowman”, “dumbbell” and “perfect Janus” are obtained, which depends on the category of organics. It is worth mention that two different topologies are obtained in one system, which is mainly determined by the density difference of two inner phases. In addition, the adjustment of oil/oil interface curvature is achieved by changing the surfactant concentration and also by the initial volume ratio of two inner phases. Moreover, the droplet size decreased significantly, from hundreds of micrometers continuously down to several micrometers is realized and more importantly, the topology of Janus droplets remains. The reported organic Janus emulsions with droplets constructed by two separated domains and sharp domain boundary would be ideal microreactors, templates for materials synthesis.