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Updated: Aug 11, 2026

Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Novel surface tension isotherm for surfactants based on local density functional theory
Simeon D Stoyanov1, Heinz Rehage, Vesselin N Paunov
1Institute of Physical Chemistry, University of Essen, Universitätstrasse 3, 45141 Essen, Germany.
Abstract:
In this Letter we report a new general method for calculating of surface tension isotherms in the presence of surfactants, based on a local density functional. We illustrate this method by deriving the interfacial tension isotherm for nonionic surfactants at an air-water or oil-water interface by using the self-consistent field theory of polymer brushes. We consider a particular case of local density functional to calculate explicitly how the interfacial tension and the surfactant adsorption depend on the surfactant bulk concentration. Experimental data for the surface tension and the surfactant adsorption isotherm for nonionic surfactants were interpreted with the help of the new isotherm. Very good agreement between the adsorption of n-dodecyl pentaoxyethylene glycol ether (C12E5) at an air-water interface, calculated from the surface tension isotherm and small-angle neutron-scattering is obtained.
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