Effects of vertical confinement on gelation and sedimentation of colloids

Azaima Razali, Christopher Fullerton, Francesco Turci, James Hallett, Robert Jack, C P Royall

Research output: Contribution to journalArticle (Academic Journal)peer-review

5 Citations (Scopus)
268 Downloads (Pure)

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, however the thickness of the “arms” of the gel is rather larger in the experiments, compared with the simulations. An analysis of local structure in the simulations showed similar behaviour to gelation in the absence of gravity.
Original languageEnglish
Pages (from-to)3230-3239
Number of pages10
JournalSoft Matter
Volume13
Issue number17
Early online date12 Apr 2017
DOIs
Publication statusPublished - 7 May 2017

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