Phase diagram of the cesium pentadecafluorooctanoate (CsPFO)/water system as determined by cesium-133 NMR: comparison with the (CsPFO)/D2O system

Boden, N.; Jolley, K. W.; Smith, Mike

doi:10.1021/j100131a043

Cited by 54 publications

(58 citation statements)

References 13 publications

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“…It forms oblate ellipsoidal micelles in water [32,33]. We have studied one micelle, an aggregate of 62 of these surfactants in a simulation box of 10,562 water molecules.…”

Section: Details Of Simulationmentioning

confidence: 99%

Dynamics of bound and free water in an aqueous micellar solution: Analysis of the lifetime and vibrational frequencies of hydrogen bonds at a complex interface

2003

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In order to understand the nature and dynamics of interfacial water molecules on the surface of complex systems, large scale, fully atomistic molecular dynamics simulations of an aqueous micelle of cesium perfluorooctanoate (CsPFO) surfactant molecules have been carried out. The lifetime and the intermolecular vibrational frequencies of the hydrogen bonds that the water molecules form with the hydrophilic, polar headgroups (PHG) of the surfactants, are calculated. Our earlier classification [1, 2, 3] of the interfacial water molecules, based on structural and energetic considerations, into bound and free type is further validated by their dynamics.Lifetime correlation functions of the water-surfactant hydrogen bonds show the long lived nature of the bound water species. Surprisingly, the water molecules that are singly hydrogen bonded to the surfactants have longer lifetime than those that form two such hydrogen bonds. The free water molecules that do not form any such 1 email:bala@jncasr.ac.in 2 email:bbagchi@sscu.iisc.ernet.in 1 hydrogen bonds behave similar to bulk water in their reorientational dynamics. A few water molecules that form two such hydrogen bonds are orientationally locked in for durations of the order of few hundreds of picoseconds, that is, much longer than their average lifetime. The intermolecular vibrational frequencies of these interfacial water molecules have been studied from the power spectra of their velocity autocorrelation function. We find a significant blue shift in the librational band of the interfacial water molecules, apart from a similar shift in the near neighbor bending modes, relative to water molecules in bulk. These blue shifts suggest an increase in rigidity in the structure around interfacial water molecules. This is in good agreement with recent incoherent, inelastic neutron scattering (IINS) data on macromolecular solutions [4]. The results of the present simulations appear to be rather general and should be relevant to the understanding of dynamics of water near any hydrophilic surface.

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“…It forms oblate ellipsoidal micelles in water [32,33]. We have studied one micelle, an aggregate of 62 of these surfactants in a simulation box of 10,562 water molecules.…”

Section: Details Of Simulationmentioning

confidence: 99%

Dynamics of bound and free water in an aqueous micellar solution: Analysis of the lifetime and vibrational frequencies of hydrogen bonds at a complex interface

2003

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“…Since traditional tools could be classified as indirect in this instance, a finding with a ''direct'' method such as cross-relaxation (where the sign of the cross-relaxation rate provides a ''null experiment'') that contradicts common belief should not just be neglected. Therefore, we chose to present here some related results on a perfluorinated surfactant where, instead of At 45°C, where the NMR measurements were performed, the sample is in the isotropic micellar phase (24). Correspondingly, the 19 F NMR spectrum, shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Water–Surfactant Contact Studied by19F–1H Heteronuclear Overhauser Effect Spectroscopy

Raulet

Furó

Brondeau

et al. 1998

Journal of Magnetic Resonance

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“…The spin scenario and the experimental implementations were performed in a lyotropic liquid crystal sample prepared with 42.5 wt % cesium-pentadecafluoroctanoate (Cs-PFO) and 57.5 wt % deuterated water (D 2 O) [24]. Cesium nuclei ( 133 Cs) are quadrupolar spin systems with I = 7/2 such that the dimension of the Hilbert space is d = 2I + 1 = 8.…”

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confidence: 99%

Classical bifurcation in a quadrupolar NMR system

et al. 2013

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The Josephson Junction model is applied to the experimental implementation of classical bifurcation in a quadrupolar Nuclear Magnetic Resonance system. There are two regimes, one linear and one nonlinear which are implemented by the radio-frequency term and the quadrupolar term of the Hamiltonian of a spin system respectively. Those terms provide an explanation of the symmetry breaking due to bifurcation. Bifurcation depends on the coexistence of both regimes at the same time in different proportions. The experiment is performed on a lyotropic liquid crystal sample of an ordered ensemble of $^{133}$Cs nuclei with spin $I=7/2$ at room temperature. Our experimental results confirm that bifurcation happens independently of the spin value and of the physical system. With this experimental spin scenario, we confirm that a quadrupolar nuclei system could be described analogously to a symmetric two--mode Bose--Einstein condensate.Comment: 5 pages, 3 figure

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Phase diagram of the cesium pentadecafluorooctanoate (CsPFO)/water system as determined by cesium-133 NMR: comparison with the (CsPFO)/D2O system

Cited by 54 publications

References 13 publications

Dynamics of bound and free water in an aqueous micellar solution: Analysis of the lifetime and vibrational frequencies of hydrogen bonds at a complex interface

Dynamics of bound and free water in an aqueous micellar solution: Analysis of the lifetime and vibrational frequencies of hydrogen bonds at a complex interface

Water–Surfactant Contact Studied by19F–1H Heteronuclear Overhauser Effect Spectroscopy

Classical bifurcation in a quadrupolar NMR system

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