The effect of lauryl alcohol on the stability of oil-in-water emulsions

Abstract

The effect of addition of lauryl alcohol was determined on the rate at which oil was separated in an ultracentrifuge from emulsions of Nujol and of olive oil in water, stabilized with 0.2% or 0.4% sodium dodecyl sulfate (SDS). In a Nujol-water-0.2% SDS emulsion with a specific interfacial area of 1.08 × 10 4 cm 2/ml emulsified oil the stability increases with added lauryl alcohol up to 56% on the basis of the SDS, after which it remains constant. The stability of the olive oil-water-SDS emulsions is unaffected by addition of lauryl alcohol. Calculations show that the increase in stability of the Nujol emulsions can be attributed to adsorption of lauryl alcohol on areas of the oil-water interface not occupied by adsorbed SDS. The absence of any stabilizing effect in the case of the olive oil emulsions is attributed to the greater solubility of lauryl alcohol in olive oil than in Nujol.