The W/W all-aqueous emulsion was made of dextran (Dex, 500 kDa, 32.5 mg/mL) and polyethylene glycol (PEG, 20 kDa, 70 mg/mL) dispersed in water. At these concentrations of polymers, and after vigorous stirring, 5-50 µm dextran enriched droplets in a PEG continuous phase were produced, forming a slightly turbid dispersion (not shown). If rested, Dex-rich droplets coalesced, further yielding macroscopic phase separation in about 1 hour, a well-known behavior .