New Method to Quantitatively Determine the Spontaneity of the Emulsification Process

A method to quantitatively determine the spontaneity ( S ) of the spontaneous emulsification process using a laser diffraction particle size analysis technique is presented. The method was experimentally tested by studying the rate of increase of the specific interfacial area (cm 2 mL - 1 s - 1 ) and the equilibrium specific interfacial area for different systems formed by the surfactant Brij30 dissolved in linear alkyl oils (C 8 −C 16 ) when brought in contact with ultrapure water. The experimental results confirmed the effectiveness of the proposed method, and they also suggest that the oil chain length of the linear alkyl oils has an important effect on the driving force of the spontaneous emulsification process in these systems. Finally, a molecular spontaneous emulsification mechanism is proposed for the systems studied.