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- Kadi, M., et al.
(författare)
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Demixing of fluorinated and hydrogenated surfactants into distinct aggregates and into distinct regions within aggregates. A combined NMR, fluorescence quenching, and cryo-TEM study
- 2002
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 18:24, s. 9243-9249
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Tidskriftsartikel (refereegranskat)abstract
- The formation of two different kinds of micelles in the cationic surfactant mixture of HFDePC and CTAC as well as the increased mixing with increasing temperature has been investigated. A critical temperature of demixing was appreciated to 42 degreesC. NMR self-diffusion measurements reveal to us a coexistence of larger fluorocarbon-rich and smaller hydrocarbon-rich micelles, which is also observed using cryo-TEM. We also suggest, from F-19 line width data, that the two surfactant species constituting the demixed micelles are I'microphase-separated. The existence of such aggregates has earlier only been speculated upon. From time-resolved fluorescence quenching measurements, we have estimated the fraction of fluorocarbon surfactant in the hydrocarbon-rich micelles to larger than 0.1.
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- Kadi, M., et al.
(författare)
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Mixed micelles of fluorocarbon and hydrocarbon surfactants. A small angle neutron scattering study
- 2004
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 20:10, s. 3933-3939
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Tidskriftsartikel (refereegranskat)abstract
- Mixtures of the partly fluorinated cationic surfactant HFDePC (N-(1, 1,2,2-tetrahydroperfluorodecanyl)pyridinium chloride and deuterated headgroup) with C(16)TAC, hexadecyl-trimethylammonium chloride, have been investigated using small angle neutron scattering with contrast matching. Earlier results from this system suggested that a demixing occurred, into two coexisting populations of micelles, hydrocarbon-rich and fluorocarbon-rich, respectively. The present results could be explained by one type of mixed micelles with an inhomogeneous distribution of fluorinated and hydrogenated surfactants within the micelles although a demixing cannot be definitely excluded.
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