The results summarized in Figure show that emulsification kinetics, as evidenced from the shift of the UV spectra, is always immensely faster in mixed solvents than in pure solvents, just is the case with both surfactant and water migrating into the organic phase from the aqueous phase below it. Diesel is essentially a mixture of various aliphatic and aromatic hydrocarbons, which thus falls in the same group as mixed solvents. Enhanced solubilities (Figure ) of the surfactants in the mixed solvent, although the underneath cause of which remain unclear, suggest that part of the effect is thermodynamic in origin, we cannot rule out the possibility that water vapor may engender an instability at the vapor-liquid interface that being the cause of the fast kinetics observed here. Another remarkable observation is that the emulsification is inhibited when either a high molecular weight hydrophilic polymer is present in the aqueous phase or when a high molecular weight hydrophobic polymer is present in the organic phase. Some of the experimental results performed with PTBS are summarized below.