Equilibrium concentration profiles and sedimentation kinetics of colloidal gels under gravitational stress - Laboratoire Charles Coulomb (L2C) Accéder directement au contenu
Communication Dans Un Congrès Journal of Physics: Condensed Matter Année : 2012

Equilibrium concentration profiles and sedimentation kinetics of colloidal gels under gravitational stress

Résumé

We study the sedimentation of colloidal gels by using a combination of light scattering, polarimetry and video imaging. The asymptotic concentration profiles $\varphi(z,t\rightarrow \infty)$ exhibit remarkable scaling properties: profiles for gels prepared at different initial volume fractions and particle interactions can be superimposed onto a single master curve by using suitable reduced variables. We show theoretically that this behavior stems from a power law dependence of the compressive elastic modulus \textit{vs} $\varphi$, which we directly test experimentally. The sedimentation kinetics comprises an initial latency stage, followed by a rapid collapse where the gel height $h$ decreases at constant velocity, and a final compaction stage characterized by a stretched exponential relaxation of $h$ towards a plateau. Analogies and differences with previous works are briefly discussed.
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Dates et versions

hal-00675086 , version 1 (29-02-2012)

Identifiants

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Stefano Buzzaccaro, Eleonora Secchi, Giovanni Brambilla, R. Piazza, Luca Cipelletti. Equilibrium concentration profiles and sedimentation kinetics of colloidal gels under gravitational stress. Eight Liquid Matter Conference, Sep 2011, Vienna, Austria. pp.284103, ⟨10.1088/0953-8984/24/28/284103⟩. ⟨hal-00675086⟩
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