Research on Colloidal Glasses

Colloids Age at Equilibrium?

Above a critical density, colloidal particles suspended in liquid will slow down and undergo a glass transition. The relaxation, or ageing, of the colloidal glass is similar to that in other non-equilibrium systems, such as spin-glasses and jammed granular matter. Despite being out of equilibrium, the concept of timescales for observables to reach equilibrium at different temperatures is useful. Ping Wang et al. [1] test this idea experimentally. They track the motion of magnetic particles within the colloidal system to determine the temperature for various modes of relaxation. And though the mobilities and diffusivities of the tracers depend on the age of the glass, they find an effective temperature, higher than the bath temperature, that controls the relaxation dynamics, as for systems at equilibrium. References:

[1] P. Wang, C. Song, and H. A. Makse, Dynamic particle tracking reveals the aging temperature of a colloidal glass, Nature Physics 2, 526-531 (2006). .ps , .pdf , including supplementary materials.


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