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arXiv · 2110.12701

Yield stress aging in attractive colloidal suspensions

Francesco Bonacci·Xavier Chateau·Eric Furst·Julie Goyon·Anaël Lemaître
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Abstract

We investigate the origin of yield stress aging in semi-dense, saline, and turbid suspensions in which structural evolution is rapidly arrested by the formation of thermally irreversible roll-resisting interparticle contacts. By performing optical tweezer (OT) three-point bending tests on particle rods, we show that these contacts yield by overcoming a rolling threshold, the critical bending moment of which grows logarithmically with time. We demonstrate that this time-dependent contact-scale rolling threshold controls the suspension yield stress and its aging kinetics. We identify a simple constitutive relation between the contact-scale flexural rigidity and rolling threshold, which transfers to macroscopic scales. This leads us to establishing a constitutive relation between macroscopic shear modulus and yield stress that is generic for an array of colloidal systems.

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Francesco Bonacci, Xavier Chateau, Eric Furst, Julie Goyon, Anaël Lemaître. 2021-10-25. Yield stress aging in attractive colloidal suspensions. https://doi.org/10.1103/physrevlett.128.018003

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