Phase behavior of platelet-shaped nanosilicate colloids in saline solutions – a small-angle X-ray scattering study. In : Proceedings of the XIIIth International Conference on Small-Angle Scattering, Kyoto, Japan, on 9-13 July 2006

D.M. Fonseca (1) , Yves Méheust (1, 2) , Jon Fossum (1) , Kenneth Knudsen (3) , K.J. Maloy (4) , K.P.S. Parmar (1)

1 Physics NTNU - Department of Physics [Trondheim]
2 GR - Géosciences Rennes
3 Institute for Energy Technology
4 UiO - University of Oslo

A study of polydisperse suspensions of fluorohectorite clay in saline solutions is presented. The suspended clay colloids consist of stacks of nanosilicate sheets several tenths of a nanometre thick. They are polydisperse both with respect to the number of stacked nanolayers and with respect to their extension along the sheets. Due to this polydispersity, a spontaneous gravity-induced vertical segregation occurs in the sample tubes and results in the presence of up to four different phases on top of each other. Precise characterization of the phase diagram of the samples as a function of salt concentration and vertical position in the tubes, based on small-angle X-ray scattering data, is presented. The vertical positions of the phase boundaries were monitored by analyzing the eccentricity of elliptic fits to iso-intensity cuts of the scattering images. The intensity profiles along the two principal directions of scattering display two power-law behaviors with a smooth transition between them and show the absence of positional order in all phases

Domaines: Minéralogie

D.M. Fonseca, Yves Méheust, Jon Fossum, Kenneth Knudsen, K.J. Maloy, et al.. Phase behavior of platelet-shaped nanosilicate colloids in saline solutions – a small-angle X-ray scattering study. In : Proceedings of the XIIIth International Conference on Small-Angle Scattering, Kyoto, Japan, on 9-13 July 2006. Journal of Applied Crystallography, 2007, 40 (s1), pp.s292-s296. ⟨10.1107/S0021889807010825⟩. ⟨insu-00177128⟩