RHEOLOGICAL BEHAVIOR OF CONCENTRATED SURFACTANT SOLUTIONS AND EMULSIONS

The rheological behaviour of oil-in-water emulsions prepared from concentrated surfactant solutions was investigated using a coaxial cylinder viscometer. The surfactant studied was a non-ionic type, namely Triton X-100. The surfactant concentration was varied up to 38.2% wt. based on the aqueous phase. The oil concentration was varied from 0 to 70% vol. The emulsions produced at high surfactant concentrations were highly flocculated in nature. The rheological behaviour of these emulsions was of the non-Newtonian, shear-thinning type. Also, the rheological data clearly indicated the presence of a yield stress. A comparison was made of the viscous flow properties of emulsions having different surfactant concentrations.