Nanoparticle-Stabilized Double Emulsions and Compressed Droplets

Stable double emulsions, both oil‐in‐water‐in‐oil and water‐in‐oil‐in‐water, stabilized by two types of nanoparticles residing at the o/w interfaces (see picture; red: CdSe quantum dots) were prepared in a simple fashion by shaking, and with narrow size distributions by microcapillary flow focusing. These double‐emulsion droplets proved stable against coalescence throughout solvent evaporation, allowing for formation of nanoparticle foams and hexagonally arrayed structures.