Janus emulsions formed with a polymerizable monomer, silicone oil, and Tween 80 aqueous solution

Tunable topology of Janus droplets composed by polymerizable monomer, silicon oil, and surfactant aqueous solution. [Display omitted] •Janus emulsions with a polymerizable monomer as inner oil phase were prepared.•The fundamentals of Janus emulsion formation were established.•The Janus topology of emulsion drops changes correspondingly with emulsion composition.•The size of Janus drops varied from hundreds to a few microns by adjusting stirring speed. Janus emulsions of a polymerizable monomer tripropyleneglycol diacrylate (TP) combined with silicone oil (SO) as inner oil phases and Tween 80 aqueous solution as continuous phase are prepared in a one-step high energy mixing process. The dependence of droplet topology on the concentration of surfactant, TP/SO ratio, and the stirring speed during emulsification is investigated. The result shows that the volume ratio of two oils within an individual droplet changes correspondingly to the total composition of emulsion. Increasing the speed of stirring results in a significant reduction in the droplet size, i.e. a five times increase in the stirring speed produces a droplet size reduction from hundreds to a few microns. What is more important, the topology of Janus drops remains similar for the different preparations. These fundamental investigations illustrate the potential for future Janus particle synthesis in batch scale with a controllable particle topology.