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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.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00003359
Contributor : Philippe Mongondry <>
Submitted on : Monday, January 5, 2004 - 9:37:43 PM
Last modification on : Tuesday, May 26, 2020 - 7:16:02 AM
Long-term archiving on: : Monday, September 20, 2010 - 11:38:03 AM

Identifiers

  • HAL Id : tel-00003359, version 2

Citation

Philippe Mongondry. Structure et comportement rhéologique des suspensions aqueuses de Laponite en présence de plusieurs additifs. Analyse de données, Statistiques et Probabilités [physics.data-an]. Université du Maine, 2003. Français. ⟨tel-00003359v2⟩

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