Mass transport phenomena in oil-in-water emulsions containing surfactant micelles: Solubilization

The influence of surfactant type and concentration on the solubilization of n-hydrocarbon emulsion droplets in aqueous solutions of nonionic surfactant micelles was investigated. Solubilization was monitored by measuring the decrease in droplet concentration with time after n-tetradecane droplets were suspended in surfactant solutions (Tween 20, Tween 40, Tween 60, Tween 80, Triton X-100, Triton SP-190, and Triton SP-175). The kinetics and extent of solubilization increased with surfactant concentration. The solubilization characteristics also depended on surfactant structure, with the interfacial mass transport coefficient and specific solubilization capacity of the micelles increasing as the HLB number moved from 17 to 12. This study shows that surfactant type and concentration have a pronounced influence on the kinetics and extent of solubilization in micellar solutions.