Echo Langevin

Fig. 3. The neutron spin echo spectrometer IN11 at the ILL Grenoble. The two large coils producing the precession fields are clearly visible (Photograph was kindly given to us by H. Biittner, Scientific Coordination Office of the Institute Laue-Langevin Grenoble).

Hellweg, Th. and Langevin, D. (1998) Bending elasticity of the surfactant film in droplet microemulsions Determination by a combination of dynamic light scattering and neutron spin-echo spectroscopy. Phys. Rev. E, 57, 6825-6834. 

Hellweg, T., Gradzielski, M., Farago, B. and Langevin, D. (2001) Shape fluctuation of microemulsion droplets A neutron spin-echo study. Colloids Surf. A, 183-185, 159-169. 

The self-diffusion approach relies on the fact that molecular displacements over macroscopic distances are very sensitive to confinement and thus to microstructure. For example, we found that at the same composition (water, oil, surfactant), the ratio between water and oil self-diffusion coefficients could differ by a factor of 100 000. This also illustrates that the microstructure is primarily determined by the spontaneous curvature of the surfactant film and not by the oil-to-water ratio. Contributions to a better understanding of microemulsion structures with FT spin-echo NMR self-diffusion starting with Stilbs, included also Nilsson, Olsson, Soderman, Khan, Guering, Monduzzi, Ceglie, Das and many others in Lund. In this work [49-63], the access to suitable systems was very important. Here, the contacts with Friberg, Shinoda, Strey and Langevin played a central role. 

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