Anne-Laure Rollet

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Measuring internuclear distances through dipolar interaction is a major challenge for solid-state nuclear magnetic resonance (NMR) spectroscopy. Obtaining reliable interatomic distances provides an access to the local structure in ordered or disordered solids. We show that at magic angle spinning (MAS) frequencies larger than ca. 50 kHz, some of the(More)
Dialkylimidazolium chlorometallate molten salts resulting from the combination of zirconium or hafnium tetrachloride and 1-butyl-3-methylimidazolium chloride, [C(1)C(4)Im][Cl], have been prepared with a molar fraction of MCl(4), R = n(MCl4)/n(MCl4) + n([C1C4IM][Cl]) equal to 0, 0.1, 0.2, 0.33, 0.5, 0.67. The structure and composition were studied by(More)
The transport properties of molten LiF-YF3 mixtures have been studied by pulsed field gradient nuclear magnetic resonance spectroscopy, potentiometric experiments, and molecular dynamics simulations. The calculated diffusion coefficients and electric conductivities compare very well with the measurements across a wide composition range. We then extract(More)
A casting process has been studied for charged polymers: the sulfonated polyimide ionomer membrane. The formation of the membrane has been followed by X-ray reflectivity as a function of temperature. The effect of equivalent weight has been also investigated. The thickness loss presents two regimes: the first one is linear vs time indicating that the models(More)
Relaxivities r1 and r2 of cobalt ferrite magnetic nanoparticles (MNPs) have been investigated in the aim of improving the models of NMR relaxation induced by magnetic nanoparticles. On one hand a large set of relaxivity data has been collected for cobalt ferrite MNP dispersions. On the other hand the relaxivity has been calculated for dispersions of cobalt(More)
Aqueous solutions of polyelectrolytes are studied here by means of neutron scattering, with emphasis on backbone hydrophobicity and counter ion specific effects. Ionene polyelectrolytes with varying chain charge density and different counter ions are considered. Their neutron scattering data feature a number of aspects and trends that clearly deviate from(More)
The local structure of molten LaF3-LiF-Li2O has been investigated by high temperature NMR spectroscopy. The (139)La and (19)F chemical shifts have been measured as a function of temperature and composition. The NMR spectra show that Li2O reacts completely with LaF3 to form a LaOF compound in the solid state below the melting temperature of the sample. LaOF(More)
The local structures of molten lanthanum alkali fluoride binaries have been studied using HT NMR technique. The chemical shifts of (19)F, (23)Na and (139)La in solid and in liquid have been compared for AF (A = alkali) and LaF(3). In pure molten alkali fluorides, the polarisability of anion-cation pairs appears to be a key parameter to depict the observed(More)
The structure of sulfonated PolyImide (sPI) ionomer membrane has been investigated via the transport properties of ions confined inside. Transport coefficients of N(CH(3))(4)(+) and Na(+) ions have been determined by several techniques in order to get a range of time/space scale as wide as possible: a method using radiotracers, conductivity, pulsed field(More)
The synthesis and structure resolution of RbLaF(4) are described. RbLaF(4) is synthesized by solid-state reaction between RbF and LaF(3) at 425 °C under a nonoxidizing atmosphere. Its crystal structure has been resolved by combining neutron and synchrotron powder diffraction data refinements (Pnma,a = 6.46281(2) Å, b = 3.86498(1) Å, c = 16.17629(4) Å, Z =(More)