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Structure et comportement rhéologique des suspensions aqueuses de Laponite en présence de plusieurs additifs

Abstract : This study deals with aqueous Laponite suspensions. The origin of gel formation has been determined by modifying interactions between particles with added salt (NaCl) or sodium pyrophosphate which slows down the aggregation of particles and with an adsorbed polymer layer (PEO). Different techniques (visual observations, static and dynamic light scattering, conventional and optical rheology) has been used to determined the structure of these suspensions at equilibrium and under shear. A new phase diagram at long time which respects the equilibrium kinetics of the suspensions from very dilute concentrations and on a large range of ionic strenghts has been obtained. Thus, we concluded on gelation through an aggregation process rather than a vitrification by repulsion of particles of Laponite suspensions. Adsorption and kinetics of adsorption of PEO on Laponite particles were studied for a large range of concentrations and molar masses of PEO. We concluded that adsorbed polymer layer is insufficient to completely screen electrostatic interactions and protect particles against aggregation. Furthermore, the high molecular weight of PEO bridge several particles and lead more resistant aggregates even under shear.
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https://tel.archives-ouvertes.fr/tel-00003359
Contributor : Philippe Mongondry <>
Submitted on : Thursday, September 11, 2003 - 5:26:14 PM
Last modification on : Tuesday, May 26, 2020 - 7:16:02 AM
Long-term archiving on: : Friday, April 2, 2010 - 7:28:21 PM

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  • HAL Id : tel-00003359, version 1

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Philippe Mongondry. Structure et comportement rhéologique des suspensions aqueuses de Laponite en présence de plusieurs additifs. Autre. Migration - université en cours d'affectation, 2003. Français. ⟨tel-00003359v1⟩

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