Stabilization of Water Droplets in an Oily Matrix Exclusively by Gel Formation

Abstract

AbstractAs droplets in emulsions are thermodynamically unstable, surfactants are required for their stabilization. However, these additives often are unwanted due to legal restrictions and possible health threats. Gelling of the aqueous phase poses one promising alternative. Only droplet‐forming processes like microfluidic devices are known to successfully work so far for stabilization by gelling. As these processes are hard to scale‐up and tend to foul, a technical alternative based on commonly used high‐pressure homogenization is investigated. A nozzle was adapted by adding a micromixer directly behind the orifice outlet. This allowed gelling and stabilizing the droplets by feeding a cold oil stream immediately after droplet breakup. Up to 40 wt‐% droplets with Sauter mean diameters down to the micrometer range could be successfully stabilized.