Generation of monodisperse gel emulsions in a microfluidic device

We demonstrate that high dispersed phase volume fraction emulsions (i.e., gel emulsions) can be prepared in situ for microfluidic applications. Previously, the production of gel-like emulsions in microfluidic devices, where the droplet size is less than the length-scale of the channel, required multistep splitting of larger droplets in a branched microchannel network. Instead, we employ an abrupt change in the aspect ratio of a single microchannel to rapidly destabilize a confined coflowing stream, forming highly monodisperse droplets (coefficient of variance < 1.5%). Using this emulsification mechanism, gel emulsions can be prepared in a single production step.