All these results with dyes confirm that the composition of the internal aqueous droplet was different than that of the external aqueous continuous phase, and show that water does not enter within oil droplets upon simple mixing as it is generally the case when preparing double emulsion via a single step method. Rather, water and only water diffuses through the oil, hydrating polymers that further form aqueous polymer-rich droplets within oil, eventually entrapping all other hydrosoluble chemicals initially present in the oily phase. Obviously, our method then allows bulk (with no limits on volumes) one step preparation of W1/O/W2 double emulsions, with the inner aqueous medium, W1, of different composition than that of the external continuous phase, W2.