An "inside-out" microfluidic approach to monodisperse emulsions stabilized by solid particles

We report a versatile "inside-out" microfluidic approach to producing monodisperse particle-stabilized emulsions, as well as supracolloidal polymer microspheres. This approach addresses the challenges faced in conventional strategies for the preparation of Pickering emulsions, that is, an insufficient control of droplet dimensions and an excess of particles in the continuous media. The proposed method minimizes waste of particles, due to their introduction in the droplet phase, rather than in the continuous medium; allows control over the coverage of droplets with particles by manipulating the concentration of particles or the flow rates of the liquids; and provides a route for an easier analysis of the dynamics of formation and buckling of Pickering emulsions.