Computer simulations of catanionic surfactants adsorbed at air/water interfaces. II. Full coverage

Authors
<div class="autor_fcen" id="1912">Clavero, E.</div>; <div class="autor_fcen" id="7362">Rodriguez, J.</div>; <div class="autor_fcen" id="4817">Laria, D.</div>
Publication Year
2007
Language
English
Format
article
Status
Published version
Description
We extend our previous molecular dynamics experiments [Rodriguez, J. Phys. Chem. B 109, 24427 (2005)] to the analysis of the adsorption of catanionic surfactants at water/air interfaces, at a surfactant coverage close to that of the saturated monolayer: 30.3 Å2 per headgroup. The mixture of surfactants investigated corresponds to equal amounts of dodecytrimethylammonium (DTA) and dodecylsulfate (DS). The structure of the interface is analyzed in terms of the local densities and orientational correlations of all relevant interfacial species. In accordance with experimental evidence, the DTA headgroups penetrate deeper into the aqueous substrate than the DS ones, although the average positions of all headgroups, with respect to the interface, lie in positions somewhat more external than the ones observed at lower coverages. Average tail tilts are close to 45°. The characteristics of the headgroup-water substrate correlations are also analyzed using a tessellation procedure of the interface. The density and polarization responses of the interfacial domains closest to the DS headgroups are enhanced, compared to those adjacent to the DTA detergents. Dynamical aspects related to the diffusion and to the orientational correlations of different water layers in close contact with the surfactant are also investigated. © 2007 American Institute of Physics.
Fil:Clavero, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Rodriguez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Laria, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Source
J Chem Phys 2007;127(12)
Subject
Adsorption
Density (specific gravity)
Molecular dynamics
Phase interfaces
Substrates
Dodecytrimethylammonium
Interfacial domains
Tessellation
Water/air interfaces
Cationic surfactants
Access level
Open access
License
http://creativecommons.org/licenses/by/2.5/ar
Repository
Biblioteca Digital (UBA-FCEN)
Institution
Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
OAI Identifier
snrd:HASH380f0781fcedd916c238af