| Rheophysical Properties of Fluorinated Non-Ionic Micellar Phases. | |
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MedLine Citation:
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PMID: 22229481 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Micellar phases can be used as templates for the preparation of mesoporous silica materials. Fluorinated and hydrogenated surfactants can provide a large variety of well-defined micellar structures: spherical and cylindrical micelles as well as more complex structures such as lamellar or sponge phases can be formed in various thermodynamic conditions. However, the preparation of ordered mesoporous materials from these organized media is not always successful for a reason not known at the moment. It thus seems of the highest importance to properly characterize the micellar solution prior to the addition of the silica precursor during the material synthesis. In this paper, we describe some rheophysical properties of the micellar phase L1 prepared with a fluorinated surfactant, the formula of which is C7F15C2H4(OC2H4)8OH labelled as RF7(EO)8. This surfactant forms micelles in water and the direct micellar phases have been characterized in a wide range of temperatures and surfactant concentrations. The rheological properties of the L1 phase have also been studied as a function of temperature and concentration. Under steady and dynamic flow conditions, the solutions behave like Newtonian or shear thinning fluids depending on the temperature and surfactant concentration. A crossover between G' and G'' is observed in the solution at the concentration of 20 wt% and at the temperature of 10°C, suggesting the presence of long entangled micelles in solution at this temperature. When subjected to the action of a shearing device, the 20 wt% solution becomes optically anisotropic and shows flow birefringence; but the average orientation of the micelles quantified by the extinction angle shows an unexpected behaviour when the shear rate is gradually increased. |
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Authors:
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Rawivan Banchathanakij; Olivier Greffier; Lydiane Bécu; Marie Jose Stebe; Jean-Luc Blin; Jean-Paul Decruppe |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-9 |
Journal Detail:
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Title: The journal of physical chemistry. B Volume: - ISSN: 1520-5207 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101157530 Medline TA: J Phys Chem B Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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