title: Equilibrium concentration profiles and sedimentation kinetics of colloidal gels under gravitational stress.
abstract: We study the sedimentation of colloidal gels by using a combination of light scattering, polarimetry and video imaging. The asymptotic concentration profiles (z,t → ∞) 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 versus , 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 toward a plateau. Analogies and differences with previous works are briefly discussed.
authors: Dipartimento di Chimica, Politecnico di Milano, 20131 Milano, Italy. stefano.buzzaccaro@mail.polimi.it
authors: S
authors: S
authors: Buzzaccaro
authors: E
authors: E
authors: Secchi
authors: G
authors: G
authors: Brambilla
authors: R
authors: R
authors: Piazza
authors: L
authors: L
authors: Cipelletti