Thermally mediated double emulsion breakup in bifurcating bi-layer microchannel

In this paper, we report the breakup dynamics of double emulsion droplets, as they flow through the bifurcating junction in bi-layer microchannel. Two cases have been investigated: the first involves double emulsion with core of water and shell of silicone oil with constant interfacial tension, this case shows that breakup dynamics of double emulsion can be demarcated into three regimes when the thermal effect is not dominant; whilst the second involves double emulsion with core of water and shell of dodecanoic acid where the thermocapillarity effect arises from change of interfacial tension subject to temperature variations. As demonstrated in the case, the Marangoni stress induced by the thermocapillary effect plays an important role in controlling the stability and release kinetics of double emulsion when flowing through complex microstructures. Our work will inspire novel applications, including droplet fission and actuation controlled by Marangoni flow via thermal mediation.