Europhys. Lett.
Volume 63, Number 6, September 2003
Page(s) 902 - 907
Section Interdisciplinary physics and related areas of science and technology
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00607-5
Europhys. Lett., 63 (6) , pp. 902-907 (2003)

Effect of surfactant structure on interfacial properties

L. Rekvig1, M. Kranenburg2, B. Hafskjold1 and B. Smit2

1  Department of Chemistry, Norwegian University of Science and Technology N-7491 Trondheim, Norway
2  Department of Chemical Engineering, University of Amsterdam Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands

(Received 15 April 2003; accepted in final form 11 July 2003)

We study surfactants at the oil/water interface using Dissipative Particle Dynamics simulations at constant $\mu_{\ab{surf}}PT$. The interfacial tension depends on the surfactant branching in a subtle way. For a given interfacial concentration, a double-tail surfactant is more efficient than its single-tail isomer only if the oil-head repulsion is sufficiently strong. For a given concentration in the bulk water phase, the single-tail surfactants are more efficient in both cases. We interpret these results in light of the molecular packing at the interface and free-energy considerations.

82.70.Uv - Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions).
68.05.-n - Liquid-liquid interfaces.

© EDP Sciences 2003