Effects of vertical confinement on gelation and sedimentation of colloids

Disordered systems under confinement may show very specific properties, such as enhanced density fluctuations or flow instabilities.

Azaima Razali (Bristol) and Christopher Fullerton (Bath, now in Montpellier) have performed experiments and simulations on the effect of extreme confinement in colloidal gels and their work (to which I have the pleasure to add my contribution) has just been published in Soft Matter.

The notable result is that while gelation is often employed in bulk systems in order to slow down sedimentation, in strongly confined systems the opposite appears to be true, with sedimentation facilitated by the formation of a percolating network.

The full article can be found here:

A. Razali, C. J. Fullerton, F. Turci,  J. E. Hallett, R. L Jack and C. P. Royall, Effects of vertical confinement on gelation and sedimentation of colloids, Soft Matter, (2017), doi:10.1039/C6SM02221A

Local structure of percolating gels at very low volume fractions

We have recently published on the Journal of Chemical Physics the study resulting from the work of a Master Student in Bristol Chemistry: via numerical simulations, we explore the very low volume fraction regime of a colloidal gel and find striking structural signatures related to the compactness of the gel arms. Moreover, we find that the only limit for gel formation truly is the accessible observation time.

Full reference: S. Griffiths, F. Turci and C. P. Royall,   The Journal of Chemical Physics 146, 014905 (2017); doi: http://dx.doi.org/10.1063/1.4973351

welcome !

I am a researcher at the School of Physics, University of Bristol (UK), working on nonequilibrium disordered systems with powerful theoretical and numerical techniques.

My focus is on emergent properties, collective behaviour and spatial structure in a wide range of systems: from glasses to animals, from gels to bones.