Structure and rheology of gel nanostructures from a vitamin C-based surfactant
| Autor: | Pierandrea Lo Nostro, Moira Ambrosi, Emiliano Carretti, Piero Baglioni, Virginia Mazzini, Emiliano Fratini, Luigi Dei |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Small-angle X-ray scattering Chemistry General Physics and Astronomy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Micelle 0104 chemical sciences Crystallography Rheology Pulmonary surfactant Lamellar phase Lamellar structure Microemulsion gel coagel lamellar phase rheology vitamin C Physical and Theoretical Chemistry 0210 nano-technology Alkyl |
| Zdroj: | Physical Chemistry Chemical Physics. 18:8865-8873 |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | The structure and rheology behaviour of gels produced by water dispersions of a vitamin C-derived surfactant (ascorbyl-6-O-dodecanoate) were investigated by means of SAXS and rheology experiments for the first time. The gel state is formed upon heating and is due to an anisotropic expansion of the tightly compact lamellar structure. The phase transition involves primarily the melting of the alkyl chains and a significant increment in the interlamellar water layer. In particular, our results show that in the gel the hydrophobic chains are in a liquid-like state, as in the core of a micelle, while the head groups release their acidic proton, become negatively charged and determine the onset of strong electrostatic interactions between facing lamellae. The full hydration of the anionic head groups and the uptake of a significant amount of water increase the interlamellar thickness and stabilise the gel structure. Rheology and SAXS measurements together provide an updated picture for the gel state. Moreover, for the first time we show the presence of a concentration threshold, above which the self-assembled aggregates interact more strongly and deplete some of the water that is retained in the interlamellar region. |
| Databáze: | OpenAIRE |
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