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arXiv · 1008.1230

Dynamic Surface Tension of Aqueous Solutions of Ionic Surfactants: Role of Electrostatics

Hernan Ritacco·Dominique Langevin·Haim Diamant·David Andelman
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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.

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Hernan Ritacco, Dominique Langevin, Haim Diamant, David Andelman. 2010-11-12. Dynamic Surface Tension of Aqueous Solutions of Ionic Surfactants: Role of Electrostatics. https://doi.org/10.1021/la103039v

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