Volume 104, 1996

Statistical thermodynamics of adsorption, micellisation and solubilisation in water–oil–surfactant systems

Abstract

We applied a self-consistent field lattice theory for chain molecules in inhomogeneous systems to a model for water–oil–nonionic surfactant. Assuming planar symmetry, the interface between macroscopic aqueous and oil phases in the presence of surfactant is examined. Our calculations reproduce oil–water phase separation, an increasing adsorption of surfactant at the planar oil/water interface upon increasing surfactant concentration and an accompanying decrease in the interfacial tension. If no micelle formation is accounted for, the tension would eventually change sign and become negative. These results are complemented by calculations on micelle formation in aqueous phases with low concentrations of dissolved oil. Upon increasing oil concentration the solubilised amount of oil per micelle and the surfactant aggregation number increase and the critical micelle concentration (c.m.c.) decreases. We pay special attention to the point where the solubility boundary of oil and the micellisation boundary intersect since this point is indicative of the properties beyond the c.m.c. and beyond the solubility boundary. Accounting for micellisation in this way, the value of the interfacial tension remains positive. For all these phenomena the effect of the variation of the surfactant tail length is considered.

Article information

Article type
Paper

Faraday Discuss., 1996,104, 167-181

Statistical thermodynamics of adsorption, micellisation and solubilisation in water–oil–surfactant systems

N. A. M. Besseling and B. P. Binks, Faraday Discuss., 1996, 104, 167 DOI: 10.1039/FD9960400167

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements