Intermediate Structures for Higher Level Arrangements: Catching Disk-Like Micelles in Decane Phosphonic Acid Aqueous Solutions
| Autor: | Marisa Alejandra Frechero, Ángel Piñeiro, J. L. Rodriguez, Pablo C. Schulz, Rosanna Marina Minardi, Erica Patricia Schulz |
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| Rok vydání: | 2013 |
| Předmět: |
Aqueous solution
Chemistry DISK-LIKE MICELLES Ciencias Químicas Mineralogy Decane MOLECULAR DYNAMICS (MD) SIMULATIONS Micelle Surfaces Coatings and Films chemistry.chemical_compound N-DECANE PHOSPHONIC ACID Química Coloidal Polymer chemistry Materials Chemistry Physical and Theoretical Chemistry CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | The Journal of Physical Chemistry B. 117:6231-6240 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp312713e |
| Popis: | It has been proposed that disk-like micelles may be precursors to the formation of lamellar liquid crystals. The possibility of obtaining n-decane phosphonic acid (DPA) disklike micelles in aqueous solution without the addition of a second ionic surfactant led us to study in detail the low-concentration range of this system by both a battery of experimental techniques and molecular dynamics (MD) simulations. The experimental results indicate that premicelles with some capacity to solubilize dyes are formed at 0.05 mM. The critical micelle concentration (cmc) was found to be 0.260 ± 0.023 mM, much lower than that previously reported in the literature. Spherical micelles, which immediately grow, leading to disk-like micelles, are probably formed at this concentration. At 0.454 ± 0.066 mM, disk-like micelles become unstable, giving rise to the formation of an emulsion of lamellar mesophase that dominates the system beyond 0.670 ± 0.045 mM. These experimental results were corroborated by MD simulations which, additionally, allow describing the structure of the obtained micelles at atomic level. The analysis of the MD trajectories revealed the presence of strong intermolecular hydrogen bonds between the surfactant headgroups, producing a compact polar layer with low water content. The formation of such H-bond network could explain the ability of this surfactant to form disk-like micelles at concentrations close to the cmc. Fil: Schulz, Erica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Piñeiro, Angel. Universidad de Santiago de Compostela. Departamento de Física Aplicada; España Fil: Rodríguez, José Luis Mariano. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Minardi, Rosanna Marina. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Schulz, Pablo Carlos. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina |
| Databáze: | OpenAIRE |
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