Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy
The composition of the adsorbed layer of a ternary surfactant mixture at the air-water interface has been studied by neutron reflectivity. The adsorption of the ternary mixture of octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene glycol monodode...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
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American Chemical Society
2017
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| _version_ | 1797060354688155648 |
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| author | Liley, J Thomas, R Penfold, J Tucker, I Petkov, J Stevenson, P Webster, J |
| author_facet | Liley, J Thomas, R Penfold, J Tucker, I Petkov, J Stevenson, P Webster, J |
| author_sort | Liley, J |
| collection | OXFORD |
| description | The composition of the adsorbed layer of a ternary surfactant mixture at the air-water interface has been studied by neutron reflectivity. The adsorption of the ternary mixture of octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene glycol monododecyl sulphate, SLES, and of each of the binary mixtures, at solution concentrations greater than the mixed critical micelle concentration (CMC) are highly non-ideal. In the ternary mixture the surface adsorption is dominated by the C12E8 and LAS, and there is little SLES at the interface. The departure from ideality in the binary mixtures can be quantitatively described by applying the pseudo{phase approximation with quadratic and cubic terms in the excess free energy of mixing (GE) both at the surface and in the micelles. The same parameters that describe the binary interactions give a quantitative fit to the adsorbed fractions in the ternary mixture over a wide range of composition. A similar analysis is effective for the mixture when SDS replaces SLES. Of the set of six GE required to fit the ternary data one is ideal (SLES-LAS) and three, LAS-C12E8 (micelle) and C12E8-SLES (micelle and surface), have minima occurring at a composition (mole fraction) of the anionic species of 1/3. |
| first_indexed | 2024-03-06T20:15:55Z |
| format | Journal article |
| id | oxford-uuid:2c2411c6-125b-4a14-9fb3-630a5d47348f |
| institution | University of Oxford |
| last_indexed | 2024-03-06T20:15:55Z |
| publishDate | 2017 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:2c2411c6-125b-4a14-9fb3-630a5d47348f2022-03-26T12:35:13ZSurface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2c2411c6-125b-4a14-9fb3-630a5d47348fSymplectic Elements at OxfordAmerican Chemical Society2017Liley, JThomas, RPenfold, JTucker, IPetkov, JStevenson, PWebster, JThe composition of the adsorbed layer of a ternary surfactant mixture at the air-water interface has been studied by neutron reflectivity. The adsorption of the ternary mixture of octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene glycol monododecyl sulphate, SLES, and of each of the binary mixtures, at solution concentrations greater than the mixed critical micelle concentration (CMC) are highly non-ideal. In the ternary mixture the surface adsorption is dominated by the C12E8 and LAS, and there is little SLES at the interface. The departure from ideality in the binary mixtures can be quantitatively described by applying the pseudo{phase approximation with quadratic and cubic terms in the excess free energy of mixing (GE) both at the surface and in the micelles. The same parameters that describe the binary interactions give a quantitative fit to the adsorbed fractions in the ternary mixture over a wide range of composition. A similar analysis is effective for the mixture when SDS replaces SLES. Of the set of six GE required to fit the ternary data one is ideal (SLES-LAS) and three, LAS-C12E8 (micelle) and C12E8-SLES (micelle and surface), have minima occurring at a composition (mole fraction) of the anionic species of 1/3. |
| spellingShingle | Liley, J Thomas, R Penfold, J Tucker, I Petkov, J Stevenson, P Webster, J Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title | Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title_full | Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title_fullStr | Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title_full_unstemmed | Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title_short | Surface adsorption in ternary surfactant mixtures above the critical micelle concentration: the effects of asymmetry on the composition dependence of the excess free energy |
| title_sort | surface adsorption in ternary surfactant mixtures above the critical micelle concentration the effects of asymmetry on the composition dependence of the excess free energy |
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