Another alternative method under study would be to produce double emulsions starting from water-in-water emulsions. These later are made of mixtures of for instance 2 segregative polymers, e.g., polyethylene glycol (PEG) and Dextran (Dex) that phase separate at a given concentration in water . Depending on the concentration and the molecular weight of both polymers, one can form Dex-rich droplets in a continuous PEG-rich continuous phase. Such systems are also known as aqueous two-phase systems (ATPS). These all-aqueous emulsions can also form from aggregative polymers, e.g., counter-charged polymers, also including small polyampholytes as adenosine triphosphate . In this case, both polymers are gathered within aqueous droplets with some remaining in the continuous phase. Such systems are also known as (complex or single) coacervates in the literature.