Scaling of Dynamics with the Range of Interaction in Short-Range Attractive Colloids

Abstract

We numerically study the dependence of the dynamics on the range of interaction Delta for the short-range square well potential. We find that, for small Delta, dynamics scale exactly in the same way as thermodynamics, both for Newtonian and Brownian microscopic dynamics. For interaction ranges from a few percent down to the Baxter limit, the relative location of the attractive-glass line and the liquid-gas line does not depend on Delta. This proves that, in this class of potentials, disordered arrested states (gels) can be generated only as a result of a kinetically arrested phase separation.

Glassy States in Asymmetric Mixtures of Soft and Hard Colloids

“…The reentrant glass observed in experiments can arise from the intervention of the demixing binodal, thus rendering the high-C glass as the result of an arrested phase separation. The latter has been extensively discussed in the literature in conjunction with gelation, and in all cases within the context of colloid-polymer mixtures with very sharp and short-range attractions caused by the polymers depleting the colloids [25,26,[28][29][30][31][32]. In that case, it has been shown [29,32] that the attractive glass line intersects the binodal on the high-density side of the glass former.…”

Self-diffusion of reversibly aggregating spheres

“…It leads to different equilibrium states depending on the volume fraction (φ) of the particles and the strength of the interaction energy (u). Weak attraction results in the formation of transient aggregates at low φ and a transient percolating network at high φ, while strong attraction may drive phase separation into a high and a low density liquid [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]. The strength of the interaction and thus the equilibrium properties are determined by the ratio of the bond formation (α) and the bond breaking (β) probability [32,33,34,35,36,37,38,39,40,41,42,43,44,45], while the kinetics of such systems depend on the absolute values of α and β.…”

Slow dynamics in a primitive tetrahedral network model

“…It has been suggested that the progressive shrinking of the unstable liquid-gas region which takes place on progressively decreasing the maximum number of bonds [15,18] is a necessary condition for observing arrest at low packing fraction in the absence of phase separation. Particles interacting only with attractive spherical potentials (beside the hard-core repulsion) can not form "equilibrium" ideal gels [19,20], since phase separation prevents the possibility of reaching in an homogeneous state low T , where the lifetime of the bond would be sufficiently long to provide a finite elasticity to the structure. Interestingly enough, network forming liquids fall in the category of limited-valency.…”