Description: MEB pictures of a double emulsion cured under UV light: partial encapsulation - Janus particle. Double emulsions are collections of droplets in droplets. These structures play an important role in various domains (such as drug delivery). Non miniaturized techniques do not succeed in controlling their sizes and their dispersitivy. In contrast, microfluidics is expected to considerably impact this domain by achieving unprecedented levels of control and producing structures impossible to obtain with the standard technologies. These aspects provide strong incentives for producing and studying these structures.