Computer simulations of catanionic surfactants adsorbed at air/water interfaces
Structural properties pertaining to the solvation of mixtures of dodecytrimethylammonium/dodecylsulfate adsorbed at water/air interfaces were studied using molecular dynamics techniques. Two different surfactant coverages, both in the submonolayer regime, were considered: an infinite-diluted catanio...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_15206106_v109_n51_p24427_Rodriguez |
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todo:paper_15206106_v109_n51_p24427_Rodriguez2023-10-03T16:20:09Z Computer simulations of catanionic surfactants adsorbed at air/water interfaces Rodriguez, J. Clavero, E. Laria, D. Air Computer simulation Interfaces (materials) Molecular dynamics Monolayers Percolation (computer storage) Surface active agents Amphiphiles Contact-head-ion-pairs (CHIP) Dodecylsulfate Dodecytrimethylammonium Equimolar mixture Submonolayer regime Positive ions Structural properties pertaining to the solvation of mixtures of dodecytrimethylammonium/dodecylsulfate adsorbed at water/air interfaces were studied using molecular dynamics techniques. Two different surfactant coverages, both in the submonolayer regime, were considered: an infinite-diluted catanionic pair and an equimolar mixture, at a surface concentration of 78.7 Å2/headgroup. The most stable solvated structures for the single surfactant pair correspond to contact-head-ion-pairs (CHIP) at a distance close to 5 Å. In addition, marginally stable solvent-separated-head-ion-pairs (SSHIP) at distances ∼ 7 Å were also observed. The mean free energy for the dissociation of CHIP was estimated to be ∼ 1 kcal/mol. At finite surfactant concentrations, one observes a considerable degree of clustering between the amphiphiles, due to the strong Coulomb coupling between headgroups. The resulting spatial domains show asymmetric structures with linear dimensions comparable to the simulation box, suggesting the onset of percolative structures. The connectivity pattern of these domains was interpreted in terms of a simplified model consisting of two-dimensional charged Lennard-Jones spheres. © 2005 American Chemical Society. Fil:Rodriguez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Clavero, E. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_15206106_v109_n51_p24427_Rodriguez |
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Universidad de Buenos Aires |
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I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Air Computer simulation Interfaces (materials) Molecular dynamics Monolayers Percolation (computer storage) Surface active agents Amphiphiles Contact-head-ion-pairs (CHIP) Dodecylsulfate Dodecytrimethylammonium Equimolar mixture Submonolayer regime Positive ions |
| spellingShingle |
Air Computer simulation Interfaces (materials) Molecular dynamics Monolayers Percolation (computer storage) Surface active agents Amphiphiles Contact-head-ion-pairs (CHIP) Dodecylsulfate Dodecytrimethylammonium Equimolar mixture Submonolayer regime Positive ions Rodriguez, J. Clavero, E. Laria, D. Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| topic_facet |
Air Computer simulation Interfaces (materials) Molecular dynamics Monolayers Percolation (computer storage) Surface active agents Amphiphiles Contact-head-ion-pairs (CHIP) Dodecylsulfate Dodecytrimethylammonium Equimolar mixture Submonolayer regime Positive ions |
| description |
Structural properties pertaining to the solvation of mixtures of dodecytrimethylammonium/dodecylsulfate adsorbed at water/air interfaces were studied using molecular dynamics techniques. Two different surfactant coverages, both in the submonolayer regime, were considered: an infinite-diluted catanionic pair and an equimolar mixture, at a surface concentration of 78.7 Å2/headgroup. The most stable solvated structures for the single surfactant pair correspond to contact-head-ion-pairs (CHIP) at a distance close to 5 Å. In addition, marginally stable solvent-separated-head-ion-pairs (SSHIP) at distances ∼ 7 Å were also observed. The mean free energy for the dissociation of CHIP was estimated to be ∼ 1 kcal/mol. At finite surfactant concentrations, one observes a considerable degree of clustering between the amphiphiles, due to the strong Coulomb coupling between headgroups. The resulting spatial domains show asymmetric structures with linear dimensions comparable to the simulation box, suggesting the onset of percolative structures. The connectivity pattern of these domains was interpreted in terms of a simplified model consisting of two-dimensional charged Lennard-Jones spheres. © 2005 American Chemical Society. |
| format |
JOUR |
| author |
Rodriguez, J. Clavero, E. Laria, D. |
| author_facet |
Rodriguez, J. Clavero, E. Laria, D. |
| author_sort |
Rodriguez, J. |
| title |
Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| title_short |
Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| title_full |
Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| title_fullStr |
Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| title_full_unstemmed |
Computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| title_sort |
computer simulations of catanionic surfactants adsorbed at air/water interfaces |
| url |
http://hdl.handle.net/20.500.12110/paper_15206106_v109_n51_p24427_Rodriguez |
| work_keys_str_mv |
AT rodriguezj computersimulationsofcatanionicsurfactantsadsorbedatairwaterinterfaces AT claveroe computersimulationsofcatanionicsurfactantsadsorbedatairwaterinterfaces AT lariad computersimulationsofcatanionicsurfactantsadsorbedatairwaterinterfaces |
| _version_ |
1782030716940320768 |