Jamming phase diagram for attractive particles

Abstract

A wide variety of systems, including granular media, colloidal suspensions and molecular systems, exhibit non-equilibrium transitions from a fluid-like to a solid-like state, characterized solely by the sudden arrest of their dynamics. Crowding or jamming of the constituent particles traps them kinetically, precluding further exploration of the phase space. The disordered fluid-like structure remains essentially unchanged at the transition. The jammed solid can be refluidized by thermalization, through temperature or vibration, or by an applied stress. The generality of the jamming transition led to the proposal of a unifying description, based on a jamming phase diagram. It was further postulated that attractive interactions might have the same effect in jamming the system as a confining pressure, and thus could be incorporated into the generalized description. Here we study experimentally the fluid-to-solid transition of weakly attractive colloidal particles, which undergo markedly similar gelation behaviour with increasing concentration and decreasing thermalization or stress. Our results support the concept of a jamming phase diagram for attractive colloidal particles, providing a unifying link between the glass transition, gelation and aggregation.

Worms under Pressure: Bulk Mechanical Properties of C. elegans Are Independent of the Cuticle

“…Similar behavior is widely observed in the jamming of emulsions or other soft colloidal suspensions, and the rearrangement of the gonad relative to other organs in Fig. 6 suggests that the internal volume may eventually become small enough that the organs, cells, and subcellular structures crowd together and cease to rearrange, leading to divergence in the apparent modulus (55)(56)(57). The linear and nonlinear mechanical properties of the worm would thus arise from two key parameters: 1) the effective volume fraction occupied by relatively incompressible internal structures, f; and 2) the intrinsic modulus of these internal structures, k 0 .…”

Rheology and phase behavior of aggregating emulsions related to droplet-droplet interactions

“…This framework comprises colloid-polymer mixtures (Trappe et al, 2001;Dawson, 2002;Bergenholtz et al, 2003).…”

“…Nevertheless, the lack of a coherent understanding of the phenomena involved usually led to semiempirical interpretations. The conceptual framework proposed in the recent literature clearly defines the role of particle concentration, interaction forces and shear stress in the aggregation and gelation of colloids (Trappe et al, 2001;Dawson, 2002;Bergenholtz et al, 2003). Relevant efforts have also been made to attain quantitative predictions of the rheometric functions in terms of colloidal interactions (see, for instance, Quemada and Berli, 2002).…”

Nanoparticle Dynamics in Polymer Melts

“…These mesostructures may or may not span the whole space depending on Φ and U [Prasad, 2003]. The rheological behaviour of weakly interacting colloidal dispersions can be rationalized with a simple two-phase model that combines the elasticity of the disordered particle network and the Newtonian viscosity of the suspending liquid [Cipelletti et al, 2000;Trappe & Weitz, 2000;Trappe et al, 2001]. Despite the complexities stemming from the intrinsic non-Newtonian feature of polymer matrices, in this chapter we show that a similar approach can be successfully applied to a series of model PNCs with weak polymer-filler interaction.…”