Abstract
The main goal of the current paper is to investigate the surface structure of ionic surfactant solutions at molecular level and the influences of the counter-ion in this course. The used methods are molecular dynamics simulation and neutral impact collision ion scattering spectroscopy. The surfactants are sodium dodecyl sulfate and cesium dodecyl sulfate. With Material Studio (MS), the concentration-depth profiles of all the components in the surface layer have been simulated. With those profiles, the surface pictures of the ionic surfactant solutions are mapped out in angstrom scale and the orientation of surface active dodecyl sulfate ion at the surface dependent on its surface density is derived. Simultaneously, neutral impact collision ion scattering spectroscopy is employed to investigate the same systems experimentally. The results indicate that the surface structure is profoundly influenced by surface density of the surfactant and specificity of the counter-ion; however, the orientation of the dodecyl sulfate ion on the surface is only subjected to its surface density but hardly affected by the properties of its counter-ion. The comparison between those simulated and experimental results reveals reasonable agreements, indicating the reliability of this investigation as well as the reliability of the simulation strategy applied in these systems.
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References
Borwankar R, Wasan DT (1986) The kinetics of adsorption of ionic surfactants at gas-liquid surfaces. Chem Eng Sci 41:199–201
Kalinin VV, Radke C (1996) An ion-binding model for ionic surfactant adsorption at aqueous fluid interfaces. Colloids Surf A 114:337–350
Warszynski P, Barzyk W, Lunkenheim K, Fruhner H (1998) surface tension and Surface potential of Na n-dodecyl sulfate at the air-solution interface: model and experiment. J Phys Chem B 102:10948–10957
Kralchevsky PA, Danov KD, Broze G, Mehreteab A (1999) Thermodynamics of ionic surfactant adsorption with account for the counterion binding: effect of salts of various valency. Langmuir 15:2351–2365
Warszynski P, Lunkenheim K, Czichocki G (2002) Effect of counterions on the adsorption of ionic surfactants at fluid−fluid interfaces. Langmuir 18:2506–2514
Gilanyi T, Varga I, Meszaros R (2004) Specific counterion effect on the adsorption of alkali decyl sulfate surfactants at air/solution interface. Phys Chem Chem Phys 6:4338–4346
Para G, Jarek E, Warszynski P (2005) The surface tension of aqueous solutions of cetyltrimethylammonium cationic surfactants in presence of bromide and chloride counterions. Colloids Surf A 261:65–73
Schulze KD, Morgner H (2006) Investigation of the electric charge structure and the dielectric permittivity at surface of solutions containing ionic surfactants. J Phys Condens Matter 18:9823–9839
Wang C (2014) Different distributions of counterions in the surface layer of cationic surfactant solutions. J Dispers Sci Technol 35:735–738
Andersson G, Krebs T, Morgner H (2005) Activity of surface active substances determined from their surface excess. Phys Chem Chem Phys 7:136–142
Morgner H, Wulf M (1995) Quantitative determination of the surface composition of binary liquid mixture: a new method and application. J Electron Spectrosc Relat Phenom 74:91–97
Andersson G, Morgner H (1998) Impact collision ion scattering spectroscopy (ICISS) and neutral impact collision ion scattering spectroscopy (NICISS) at surfaces of organic liquids. Surf Sci 405:138–151
Andersson G, Morgner H (2000) Investigations on solutions of tetrabutylonium salts in formamide with NICISS and ICISS: concentration depth profiles and composition of the outermost layer. Surf Sci 445:89–99
Hantal G, Partay L, Varga I, Jedlovszky P, Gilanyi T (2007) Counterion and surface density dependence of the adsorption layer of ionic surfactants at the vapor-aqueous solution interface: a computer simulation study. J Phys Chem B 111:1769–1774
Zhao T, Xu G, Yuan S, Chen Y, Yan H (2010) Molecular dynamics study of alkyl benzene sulfonate at air/water interface: effect of inorganic salts. J Phys Chem B 114:5025–5033
Yan H, Guo X, Yuan S, Liu C (2011) Molecular dynamics study of the effect of calcium ions on the monolayer of SDC and SDSn surfactants at the vapor/liquid interface. Langmuir 27:5762–5771
Cao X, Lu K, Cui X, Shi J, Yuan S (2010) Interactions between anionic surfactants and cations. Acta Phys -Chim Sin 26:1579–1964
Eastoe J, Nave S, Downer A, Paul A, Rankin A, Tribe K, Penfold J (2000) Adsorption of ionic surfactants at the air-solution interface. Langmuir 16:4511–4518
An SW, Lu JR, Thomas RK (1996) Apparent anomalies in surface excesses determined from neutron reflection and the Gibbs equation in anionic surfactants with particular reference to perfluorooctanoates at the air/water interface. Langmuir 12:2446–2453
Eastoe J, Dalton J, Rogueda P, Sharpe D, Dong J, Webster JRP (1996) Interfacial properties of a catanionic surfactant. Langmuir 12:2706–2711
Schlossman ML (2002) Liquid–liquid interfaces: studied by X-ray and neutron scattering. Curr Opin Colloid Interface Sci 7:235–243
Moebius D, Miller R (2001) Stud Interface Sci 11:205 Elsevier
Koelsch P, Viswanath P, Motschmann H, Shapovalov V, Brezesinski G, Mohwald H, Horinek D, Netz RR, Giewekemeyer K, Salditt T, Schollmeyer H, Von Klitzing R, Daillant J, Guenoun P (2007) Specific ion effects in physicochemical and biological systems: simulations, theory and experiments. Colloids Surf A 303:110–136
Wang C, Morgner H (2011) Distribution of the surfactant ions near the surface of non-aqueous solution gained by angular resolved X-ray photoelectron spectroscopy. Microchim Acta 171:415–422
Wang C, Morgner H (2011) Molar concentration-depth profiles at the solution surface of a cationic surfactant reconstructed with angular resolved X-ray photoelectron spectroscopy. Appl Surf Sci 257:2291–2297
Wang C, Andersson G (2011) Measuring concentration depth profiles at liquid surfaces: comparing angle resolved X-ray photoelectron spectroscopy and neutral impact collision scattering spectroscopy. Surf Sci 605:889–897
Pohl H, Manzoor R, Morgner H (2013) Adsorption behavior of the ternary system of phospholipid 1-palmitoyl-2-oleoyl-sn-gylycero-3-phosphocholine in 3-hydroxypropionitrile with added tetrabutylammonium bromide. Surf Sci 618:12–19
Andersson G, Morgner H, Pohl H (2008) Energy-loss straggling of helium projectiles at low kinetic energies: deconvolution of concentration depth profiles of inorganic salt solutes in aqueous solutions. Phys Rev A 78:032904
Pohl H, Krebs T, Morgner H (2010) Orientation of 1-palmitoyl-2-oleoyl-sn-gylycero-3-phosphocholine at the surface of formamide and hydroxypropionitrile. Langmuir 26:2473–2476
Wang C, Morgner H (2010) Effects of counterions on adsorption behavior of anionic surfactants on solution surface. Langmuir 26:3121–3125
Wang C, Morgner H (2011) The competitive adsorption of counter-ions at the surface of anionic surfactants solution. Phys Chem Chem Phys 13:3881–3885
Wang C, Morgner H (2014) The dependence of surface tension on surface properties of ionic surfactant solution and the effects of counter-ion therein. Phys Chem Chem Phys 16:23338–23364
Andersson G, Ridings C (2014) Ion scattering studies of molecular structure at liquid surfaces with applications in industrial and biological systems. Chem Rev 114:8361–8387
Tang X, Koenig PH, Larson RG (2014) Molecular dynamics simulations of sodium dodecyl sulfate micelles in water: the effect of the force field. J Phys Chem B 118:3864–3880
Abel S, Dupradeau F, Marchi M (2012) Molecular dynamics simulations of a characteristic DPC micelle in water. J Chem Theory Comput 8:4610–4623
Zavitsas AA (2001) Properties of water solution of electrolytes and nonelectrolytes. J Phys Chem B 105:7805–7817
Jungwirth P, Tobias DJ (2002) Ions at the air/water interface. J Phys Chem B 106:6361–6373
Acknowledgments
This work is supported by National Natural Science Foundation of China (Grants No. 21203251 and 21203250) and Ministry of Education of China (Ph.D. Programs Foundation Grant No. 20120133120008 and Scientific Research Foundation for Returned Scholars). The financial support from Fund for Distinguished Young Scientists of Shandong Province (Grant No. BS2013NJ008) is also gratefully thanked.
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Wang, C., Tan, Y., Jiang, Z. et al. Molecular structure of ionic surfactant solution surface and effects of counter-ion therein—a joint investigation by simulation and experiment. Colloid Polym Sci 293, 3479–3486 (2015). https://doi.org/10.1007/s00396-015-3685-6
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DOI: https://doi.org/10.1007/s00396-015-3685-6