The structure and stability of multiple micro-droplets

Microfluidic droplet-on-demand systems allow the controllable construction of multiple droplets of previously unattainable morphologies. Guided by the diagrams of the possible topologies of double droplets we investigate in detail the vistas to control the morphology of Janus droplets. We also explore and control new morphologies of multiple Janus droplets, i.e., arbitrarily long chains of alternating immiscible segments. Theoretical calculations together with the control offered by the use of automation allow the design of both the topology and the geometry (e.g. curvatures of the interfaces) of the multiple droplets. The ability to rationally design convex–convex, convex–concave and concave–convex segments may be useful in material science, while the ability to tune the distances between the interfaces in the chains of droplets may have applications in designing artificial biochemical signalling networks.