Altogether, this shows that the internal droplets, within the oil droplets, are indeed an aqueous phase and that PEG is dispersed within. As well, PEG no longer remained within the 1-Octanol since the outer shell around the internal droplet clearly lacked fluorescence. Note though that small amount of PEG was released in the outer PVA continuous phase, accounting for the slight outer fluorescence. This also confirms that water diffuses through 1-octanol, affording hydration of the PEG within, and formation of aqueous droplets in oil, and then, a double emulsion. For more information, we planned to disperse hydrosoluble dyes, like sulforhodamine B or BSA-FITC into the oily phase. This requires adding water and butanol in the PEG-octanol phase: with these additives, a microemulsion can successfully be obtained in the oil phase. We believe that PEG and butanol both help the formation of such a W/O microemulsion. The final/optimal composition of this oily phase was then PEG (10%) in octanol (25mL)-butanol (5mL) plus water (200 µL). Interestingly, the dispersion was limpid and fluid at room temperature, no longer gelling upon cooling as in the case of water and butanol free mixtures.