Volume 59, Number 1, July 2002
|Page(s)||55 - 61|
|Section||Condensed matter: structure, mechanical and thermal properties|
|Published online||01 June 2002|
The measurement by SAXS of the nematic order parameter of laponite gels
Laboratoire de Physique des Solides, UMR CNRS 8502 Bâtiment 510, Université Paris-Sud - 91405 Orsay, France
2 European Synchrotron Radiation Facility - BP 220, 38043 Grenoble, France
3 Sciences Moléculaires aux Interfaces, FRE CNRS 2068 2 rue de la Houssinière, BP 32229, 44322 Nantes, France
4 Nanomix Inc. - 1295 A 67th Street, CA 94608, Emeryville, USA
Corresponding author: firstname.lastname@example.org
Accepted: 15 April 2002
We performed small-angle X-ray scattering (SAXS) experiments on oriented samples of laponite clay gels obtained by slow evaporation. The SAXS patterns are clearly anisotropic, which demonstrates the existence of nematic-like orientational correlations of the laponite disc-like particles. The iso-intensity lines of the SAXS patterns are elliptical and roughly homothetic over the whole scattering vector range examined in this experiment. The value of the nematic order parameter, , derived from the SAXS patterns is comparable to that of usual liquid crystals. This large value proves the importance of orientational correlations in these gels at concentrations higher than , even in the absence of shear.
PACS: 61.10.-i – X-ray diffraction and scattering / 61.30.-v – Liquid crystals / 82.70.-y – Disperse systems; complex fluids
© EDP Sciences, 2002
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