Light scattering study of solubilization of emulsion droplets by non-ionic surfactant solutions

Abstract

Abstract Light scattering (dynamic and static) and turbidity measurements were used to monitor the time dependence of the concentration and size of n-hexadecane emulsion droplets (initial diameter ≈ 0.43 mm) dispersed in non-ionic surfactant solutions (2 wt.% polyoxyethylene sorbitan monolaurate). The concentration of droplets decreased with time as n-hexadecane molecules were solubilized by surfactant micelles, but the droplet size distribution remained constant. The results are consistent with a mechanism in which oil molecules are exchanged between emulsion droplets and surfactant micelles at the oil/water interface. The measured solubilization kinetics appear to be dominated by interfacial transport processes, and can be predicted by an interfacial mass transfer coefficient of 9.7 × 10−6 cm min−1.