Fig. 1: Oil droplets formation by air-assisted step-emulsification.
From: Gas-assisted microfluidic step-emulsification for generating micron- and submicron-sized droplets
a Schematic diagram of the device for producing hollow-core double emulsions. The air, oil (FC40) and SDS aqueous solutions are the inner disperse, outer disperse and continuous phases, respectively. The air meets the oil phase at the first junction (J1), and the air-oil compound threads meet the aqueous phase at the second junction (J2). Hollow-core double emulsions are formed at the step. Further downstream in the reservoir, the air cores shrink and disappear or diffuse into air “balloon” bubbles, leaving oil single-emulsion droplets. b Top view experimental image of the microfluidic device in (a). c Close-up top view experimental image of the interfaces separating the three fluid phases in the Hele-Shaw channel. d Self-assembled hollow-core double emulsions in the reservoir close to the step. e A mixture of oil single drops and large air balloons downstream in the reservoir. Scale bar lengths are 200 μm in (b), 100 μm in (c) and (d), and 50 μm in (e)
