By contrast, addition of carboxymethyl Dextran derivative (CM-Dex, 150 kDa, 5% in water, 200 µL in 1 mL double-like emulsion) to the initial double-like emulsion yielded destabilization (figure ). Droplets exhibited a size similar to that of 'simple' Dex-in-PEG all-aqueous emulsion, coalescence of droplets was also observed, which could also spread on the glass microscopy slide. The use of Nile red and CM-DexFITC allowed observing red and green patches and droplets (figure and). By contrast to what occurs when adding DexSulf, in this case, this suggests that CM-Dex probably covered the small oil-in-water droplets, interacting with CTAB and then get sequestered within the Dex-rich phase. This could be expected since CM-Dex alone is also sequestered within the Dex-rich phase in 'simple' Dex-in-PEG all-aqueous emulsion (not shown). The all-aqueous emulsion was no longer stabilized in these conditions. Then, to this unstable emulsion, DexSulf was added as above under vigorous vortexing (DexSulf, 200 µL in 1 mL double-like emulsion that also contained 200 µL CM-Dex). This yielded stable and smaller droplets, the size of which was similar to that observed in figure . The use of both Nile red and DexSulfFITC allowed observing fluorescent circles (figure and), attesting that oil droplets interacted with DexSulf and again covered Dexrich droplets. By contrast, the use of CM-DexFITC allowed observing small fluorescent droplets (figure ), showing that this polymer remained entrapped within the Dex-rich phase. It is expected that the sulfate groups of DexSulf interact much more strongly with the tetrabutyl ammonium moiety of CTAB than do the carboxylate groups of CM-Dex. As a consequence, the oil droplets stabilized by CTAB are no longer covered by CM-Dex, but by DexSulf, allowing these colloidal droplets to move back to the interface of Dex-rich droplets and the PEG-rich continuous phase, leaving CM-Dex within droplets. This can then be a nice way to encapsulate negatively charged chemicals in such double-like emulsion.