Issue 38, 2023

Hydrodynamic lubrication in colloidal gels


Colloidal gels are elasto-plastic materials composed of an out-of-equilibrium, self-assembled network of micron-sized (solid) particles suspended in a fluid. Recent work has shown that far-field hydrodynamic interactions do not change gel structure, only the rate at which the network forms and ages. However, during gel formation, the interplay between short-ranged attractions leading to gelation and equally short-ranged hydrodynamic lubrication interactions remains poorly understood. Here, we therefore study gelation using a range of hydrodynamic descriptions: from single-body (Brownian Dynamics), to pairwise (Rotne–Prager–Yamakawa), to (non-)lubrication-corrected many-body (Stokesian Dynamics). We confirm the current understanding informed by simulations accurate in the far-field. Yet, we find that accounting for lubrication can strongly impact structure at low colloid volume fraction. Counterintuitively, strongly dissipative lubrication interactions also accelerate the aging of a gel, irrespective of colloid volume fraction. Both elements can be explained by lubrication forces facilitating collective dynamics and therefore phase-separation. Our findings indicate that despite the computational cost, lubricated hydrodynamic modeling with many-body far-field interactions is needed to accurately capture the evolution of the gel structure.

Graphical abstract: Hydrodynamic lubrication in colloidal gels

Article information

Article type
16 Jun 2023
15 Sep 2023
First published
18 Sep 2023
This article is Open Access
Creative Commons BY license

Soft Matter, 2023,19, 7388-7398

Hydrodynamic lubrication in colloidal gels

K. W. Torre and J. de Graaf, Soft Matter, 2023, 19, 7388 DOI: 10.1039/D3SM00784G

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