The effect of blending emulsifiers/surfactants on emulsion stability
Abstract
The effect of blending surfactants on emulsion stability was studied. Emulsions whose Phase Inversion Temperature (PIT) is quit high above the storage temperature are stable, and such products have a long shelf life.
In this work, the emulsion system consists of water (aqua phase) and cyclohexane (oil phase). The surfactants/emulsifiers used are tween 20 and cetyl alcohol.
First, an emulsion of water/tween 20/cyclohexane was prepared in proportions of 48.5%w/w,
3%w/w and 48.5%w/w respectively and the PIT determined. Then both surfactants were blended in equal proportions with the same amounts of water and cyclohexane, and the new PIT was determined using the conductimetry method.
It was found out that the PIT of the emulsion when only tween 20 is used as the surfactant was 45 ˚C and that when both tween 20 and cetyl alcohol were used as emulsifiers was 42 ˚C. Hence, from the observations, blending surfactants has a negative effect on emulsion stability; i.e. lowers the emulsion PIT which facilitates de-emulsification processes.