Dynamic Surface Tension of Aqueous Solutions of Ionic Surfactants: Role of Electrostatics
Abstract
The adsorption kinetics of the cationic surfactant dodecyltrimethylammonium bromide at the air-water interface has been studied by the maximum bubble pressure method at concentrations below the critical micellar concentration. At short times, the adsorption is diffusion-limited. At longer times, the surface tension shows an intermediate plateau and can no longer be accounted for by a diffusion limited process. Instead, adsorption appears kinetically controlled and slowed down by an adsorption barrier. A Poisson-Boltzmann theory for the electrostatic repulsion from the surface does not fully account for the observed potential barrier. The possibility of a surface phase transition is expected from the fitted isotherms but has not been observed by Brewster angle microscopy.
Keywords
Cite
@article{arxiv.1008.1230,
title = {Dynamic Surface Tension of Aqueous Solutions of Ionic Surfactants: Role of Electrostatics},
author = {Hernan Ritacco and Dominique Langevin and Haim Diamant and David Andelman},
journal= {arXiv preprint arXiv:1008.1230},
year = {2011}
}
Comments
13 pages, 5 figures