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

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• 作者：Herna虂n Ritacco ; Dominique Langevin ; Haim Diamant ; David Andelman
• 刊名：Langmuir
• 出版年：2011
• 出版时间：February 1, 2011
• 年：2011
• 卷：27
• 期：3
• 页码：1009-1014
• 全文大小：815K
• 年卷期：v.27,no.3(February 1, 2011)
• ISSN：1520-5827

文摘

The adsorption kinetics of the cationic surfactant dodecyltrimethylammonium bromide at the air鈭抴ater 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鈭払oltzmann 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.