Effects of vertical confinement on gelation and sedimentation of colloids

Razali, Azaima and Fullerton, Christopher J. and Turci, Francesco and Hallett, James E. and Jack, Rob L. and Royall, C. Patrick (2017) Effects of vertical confinement on gelation and sedimentation of colloids. Soft Matter, 13 (17). pp. 3230-3239. E-ISSN 1744-6848

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Abstract

We consider the sedimentation of a colloidal gel under confinement in the direction of gravity. The confinement allows us to compare directly experiments and computer simulations, for the same system size in the vertical direction. The confinement also leads to qualitatively different behaviour compared to bulk systems: in large systems gelation suppresses sedimentation, but for small systems sedimentation is enhanced relative to non-gelling suspensions, although the rate of sedimentation is reduced when the strength of the attraction between the colloids is strong. We map interaction parameters between a model experimental system (observed in real space) and computer simulations. Remarkably, we find that when simulating the system using Brownian dynamics in which hydrodynamic interactions between the particles are neglected, we find that sedimentation occurs on the same timescale as the experiments. An analysis of local structure in the simulations showed similar behaviour to gelation in the absence of gravity.

Item Type:	Article (Journal)
Additional Information:	8797/70400
Uncontrolled Keywords:	vertical confinement, gelation, sedimentation, colloids
Subjects:	Q Science > QC Physics Q Science > QD Chemistry
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Science
Depositing User:	Dr Azaima Razali
Date Deposited:	29 Mar 2019 09:27
Last Modified:	12 Jul 2019 12:00
URI:	http://irep.iium.edu.my/id/eprint/70400

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