Non-equilibrium behavior of sticky colloidal particles: beads, clusters and gels

Sedgwick, Helen; Kroy, Klaus; Salonen, Anniina; Robertson, Malcolm B.; Egelhaaf, Stefan U.; Poon, Wilson

doi:10.1140/epje/e2005-00009-x

Cited by 68 publications

(109 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar peak at low q is obtained in the system without phase transition, due to local compaction of the system [7]. The arrested phase separation scenario is fully in agreement with figure 1 and with previous findings in simulations and experiments; the resulting gels are heterogeneous locally and show arrested dynamics [2,3,5].…”

Section: Resultssupporting

confidence: 89%

Competition between glass transition and liquid–gas separation in attracting colloids

Puertas

Fuchs

Cates

2007

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We present simulation results addressing the phenomenon of colloidal gelation induced by attractive interactions. The liquid-gas transition is prevented by the glass arrest at high enough attraction strength, resulting in a colloidal gel. The dynamics of the system is controlled by the glass, with little effect of the liquidgas transition. When the system separates into liquid and vapour phases, even if the denser phase enters the non-ergodic region, the vapour phase enables the structural relaxation of the system as a whole.

show abstract

Section: Resultssupporting

confidence: 89%

Competition between glass transition and liquid–gas separation in attracting colloids

Puertas

Fuchs

Cates

2007

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…21 A fuller understanding of DH in dense colloids with short-range attractions must include some of these same elements but may also involve an interplay between arrest and incipient phase separation (or, in our simulations, incipient microphase separation), which has long been argued to play a strong role in colloidal gelation at low density. 22,50 …”

Section: Discussionmentioning

confidence: 99%

Mode Coupling and Dynamical Heterogeneity in Colloidal Gelation: A Simulation Study

2005

View full text Add to dashboard Cite

We present simulation results addressing the dynamics of a colloidal system with attractive interactions close to gelation. Our interaction also has a soft, long-range repulsive barrier that suppresses liquid-gas type phase separation at long wavelengths. The new results presented here lend further weight to an intriguing picture emerging from our previous simulation work on the same system. Whereas mode coupling theory (MCT) offers quantitatively good results for the decay of correlators, closer inspection of the dynamics reveals a bimodal population of fast and slow particles with a very long exchange time scale. This population split represents a particular form of dynamic heterogeneity (DH). Although DH is usually associated with activated hopping and/or facilitated dynamics in glasses, the form of DH observed here may be more collective in character and associated with static (i.e., structural) heterogeneity.

show abstract

“…For a very slow quench, the system first demixes locally and then coarsens, until the denser coexisting phase, whose properties continue to evolve, arrests by a CMCT-like mechanism (merging with bare MCT at high enough density). Slow quenches have recently been examined experimentally, and these ideas may account for a surprising "bead phase" seen at low φ [17].…”

Section: Pacs Numbersmentioning

confidence: 99%

Cluster Mode-Coupling Approach to Weak Gelation in Attractive Colloids

2004

Self Cite

View full text Add to dashboard Cite

Mode-coupling theory (MCT) predicts arrest of colloids in terms of their volume fraction, and the range and depth of the interparticle attraction. We discuss how effective values of these parameters evolve under cluster aggregation. We argue that weak gelation in colloids can be idealized as a two-stage ergodicity breaking: first at short scales (approximated by the bare MCT) and then at larger scales (governed by MCT applied to clusters). The competition between arrest and phase separation is considered in relation to recent experiments. We predict a long-lived 'semi-ergodic' phase of mobile clusters, showing logarithmic relaxation close to the gel line. PACS numbers:Hard-sphere colloids with short-range attractions can undergo several types of arrest. At high densities they show two distinct glass transitions (repulsion-driven and attraction-driven), with a re-entrant dependence on attraction strength [1]. This scenario was first predicted by mode coupling theory (MCT) [2,3,4], and depends on both the attraction range δ (in units of particle diameter) and well-depth ε (in units of k B T ). MCT is remarkably successful, at least for large volume fractions φ 0.4.At lower volume fractions, however, there is no comparable theoretical framework. Yet 'weak gelation', in which bonding is strong but not so strong as to be irreversible, can lead to nonergodic soft solids, of nonzero static elastic modulus, at volume fractions of just a few percent [5]. It might be argued that a finite modulus requires a percolating network of bonds whose lifetime exceeds that of the experiment. However this is simplistic: as shown by the case of repulsive glasses, a finite modulus can arise with no bonding at all. We argue here that the rigidity of weak gels arises not from bond percolation but from kinetic ergodicity breaking [6], just as it does in glass formation. This suggests that an MCT-like approach to weak gelation could be fruitful.MCT takes its structural input from equilibrium liquid state theory; it cannot address states of arrest where this structure is strongly perturbed [7]. This matters relatively little at φ 0.4, where each particle interacts with many others, and not much room is left for structural development upon a quench. But more severe consequences must be expected at low volume fractions where strongly nonuniform, ramified gels arise. Here the pathway to complete nonergodicity (starting from a homogenized fluid sample, say) must involve a nontrivial episode of structure formation, akin to irreversible cluster aggregation (ICA). Such kinetics certainly dominates for irreversible ("strong") gelation (ε −1 = 0), where particles aggregate on contact into clusters, with various kinetic universality classes [8]. Relative simplicity is restored at low φ thanks to the invariance of this aggregation process under coarse graining in the (ordered) limit δ, ε −1 → 0 and φ → 0. This scaling limit is controlled by an ICA 'fixed point', where details of the short-ranged attraction are irrelevant. The resulting fractal cluster...

show abstract

Non-equilibrium behavior of sticky colloidal particles: beads, clusters and gels

Cited by 68 publications

References 31 publications

Competition between glass transition and liquid–gas separation in attracting colloids

Competition between glass transition and liquid–gas separation in attracting colloids

Mode Coupling and Dynamical Heterogeneity in Colloidal Gelation: A Simulation Study

Cluster Mode-Coupling Approach to Weak Gelation in Attractive Colloids

Contact Info

Product

Resources

About