rheological study of a pickering emulsion stabilized by algerian clay particles

A pickering oil/water (o/w) emulsion was formulated based on algerian bentonite particles with small amounts of synthetic surfactant ranging between 0.01 and 0.05 %. a rheological study was carried out on the emulsions studied after 18 months of aging using a parallel plate geometry. the rheological study, under variable shear, has shown that the viscous behavior of these emulsions is of structural type, with the presence of two newtonian regions at low and high shear. the oscillatory test revealed that emulsions have the character of a viscoelastic gel which is practically insensitive to frequency decreasing sweep and therefore potentially stable over time. results showed that 7% of bentonite and 0.015% of cationic surfactant (cetyltrimethylammonium bromide) are necessary to obtain a pickering emulsion with an adequate rheological behavior for a cutaneous application.