Slow dynamics in glassy soft matter

Abstract

Abstract.Measuring, characterizing and modelling the slow dynamics of glassy soft matter is a great challenge, with an impact that ranges from industrial applications to fundamental issues in modern statistical physics, such as the glass transition and the description of out-of-equilibrium systems. Although our understanding of these phenomena is still far from complete, recent simulations and novel theoretical approaches and experimental methods have shed new light on the dynamics of soft glassy materials. In this paper, we review the work of the last few years, with an emphasis on experiments in four distinct and yet related areas: the existence of two different glass states (attractive and repulsive), the dynamics of systems very far from equilibrium, the effect of an external perturbation on glassy materials, and dynamical heterogeneity.

Slow dynamics, aging, and glassy rheology in soft and living matter

“…A feature of systems near the jamming transition, such as supercooled liquids and glasses, is the presence of dynamical heterogeneities [20,61]. The slow and heterogeneous dynamics in jammed systems such as sand [62], colloidal hard sphere glasses [63] and coarsening foams [64] have been studied in detail.…”

“…The interaction between the individual constituents of soft materials can be tuned easily [17] and this feature is exploited for example in the verification of the predictions of the MCT for repulsive and attractive colloidal glasses [18,19]. For a more complete discussion, we would like to refer the readers to a recent review article by Cipelletti and Ramos [20].…”

Ultra-long-range dynamic correlations in a microscopic model for aging gels

“…When the dense phase forms an amorphous solid, the phase separation is kinetically hindered [13][14][15][16] and a gel forms. The microscopic dynamical and structural properties of these nonequilibrium gels evolve slowly with time.This aging dynamics has been the subject of many experimental studies, which established that aging in colloidal gels is 'anomalous' [17,18], i.e. it differs qualitatively from the aging observed in conventional glassy materials, such as polymer and colloidal glasses [19,20].…”

“…Finally, spatiallyresolved dynamic measurements revealed the existence of long-ranged correlations extending up to the system size [27,28], again contrasting with the much smaller-ranged dynamic heterogeneity observed in glassy materials [29]. Such peculiar behaviour is hypothesized to follow from the infrequent release of 'internal stresses' that relax the fractal network [18], but this interpretation remains to be confirmed by direct observation. This overall phenomenology has been reported for laponite, carbon black, micellar polycrystals, multilamellar vesicles, implying it is generic to a large class of soft materials [18].…”

Monitoring Spatially Heterogeneous Dynamics in a Drying Colloidal Thin Film

“…The method of TRC determines the correlation coefficient c(t, τ) by multiplying two far-field speckle images taken at time t and t + τ without any need for further time averaging [7]. It is now possible to monitor the amount of correlation c(t, τ) as a function of correlation time τ, as it is done in a traditional experiment c(t, τ) t = g 2 (τ) − 1, or as a function of t. The advent of this new technique has revealed that intermittency is intimately related to the slow glassy dynamics observed in many dense complex systems [7,8].…”