Doctoral theses
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Identifier |
000405245 |
Title |
Microscopic Dynamics and Rheology of Colloidal Gels |
Alternative Title |
Αργή δυναμική και γήρανση κολλοειδών υάλων και πηκτωμάτων |
Author
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Moghimi, Esmaeel
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Thesis advisor
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Πετεκίδης, Γεώργιος
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Reviewer
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Φυτάς, Γεώργιος
Βλασσόπουλος, Δημήτριος
Βαμβακάκη, Μαρία
Benoit, Loppinet
Philippe, Coussot
Stefan, Egelhaaf
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Abstract |
In this dissertation we examine both linear and nonlinear response rheology of concentrated colloidal
suspensions with attractive interactions using a combination of experiments and Brownian Dynamics
(BD) simulations with the view towards understanding the link between microstructure and
mechanical properties. The experimental model system is depletion colloid-polymer mixture
comprising of a hard sphere (PMMA particles) colloidal suspension with the addition of non adsorbing
linear polymer chains as depletant. We study a range of particle volume factions and attraction
strengths exploring from a low particle volume fraction gel to highly dense attractive glassy state. We
also perform Brownian Dynamics (BD) simulations in order to get both rheological and detailed
structural information. We have studied four topics in this work: We first examine yielding of attractive
glasses during start-up shear flow. For a fixed volume fraction of φ = 0.62, a wide range of attraction
strengths and the ranges of attraction is investigated. We second, examine both linear and nonlinear
response rheology of colloidal gels. A range of volume fractions, gel ages, and bond strengths are
investigated. In the third part, we study by rheology and Brownian dynamics (BD) simulations the
decay of stress over time after shear cessation of a well-developed steady shear flow in an
intermediate volume fraction particle gel (φ = 0.44). In the last part, we interrogate both structural and
mechanical properties of the gel during flow and its time evolution after shear cessation for both
steady and oscillatory shear flow by a combination of experiments and BD simulations providing a
link between structural and mechanical properties of the gel.
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Language |
English |
Subject |
Attractive colloidal glasses |
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Brownian Dynamics simulations |
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Προσομοιώσεις Brownian δυναμικής |
Issue date |
2017-02-10 |
Collection
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School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Doctoral theses
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Type of Work--Doctoral theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/a/f/0/metadata-dlib-1495188872-870517-8493.tkl
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