Re-entrant Glass Transition in a Colloid-Polymer Mixture with Depletion Attractions

Abstract

Performing light scattering experiments we show that introducing short-ranged attraction to a colloidal suspension of nearly hard spheres by addition of free polymer produces new glass transition phenomena. We observe a dramatic acceleration of the density fluctuations amounting to the melting of a colloidal glass. Increasing the strength of the attractions the system freezes into another nonergodic state sharing some qualitative features with gel states occurring at lower colloid packing fractions. This reentrant glass transition is in qualitative agreement with recent theoretical predictions.

Bond formation and slow heterogeneous dynamics in adhesive spheres with long-ranged repulsion: Quantitative test of mode coupling theory

“…The exponent parameter λ enters in the second order of the asymptotic expansion of the right-hand side of Eqs. (3,5) around the critical plateau f c q . Therefore it depends on the structure factor S c q at the critical point via the vertex Eq.…”

“…Weak short ranged attractions at first melt these 'repulsion-driven glasses' because they distort and loosen the local packing. At attraction strengths somewhat higher, yet still of the order of the thermal energy, physical bonds are formed in dense systems, which leads to aggregation into 'attraction driven glasses' [3,4,5]. At attraction strengths high compared to thermal fluctuations aggregation phenomena proceed far from equilibrium at low density, resulting in tenuous solids, i.e.…”

Glass–glass transition during aging of a colloidal clay

“…Normally, these are triggered by a modification of the effective interparticle interactions that is obtained though a change of external parameters. For example, multiple glassy states were first experimentally observed in suspensions of hard-sphere-like particles such as sterically stabilized polymethylmethacrylate particles 3 or highly cross-linked microgel particles 4 , upon addition of non-adsorbing polymers. In these systems, a glassglass transition occurs from the well-known hard sphere glass 9 , due to caging in the absence of polymers, to a second glass, stabilized by the short-range attractive depletion interactions, on increase of polymer concentration 13 .…”

“…In these systems, a glassglass transition occurs from the well-known hard sphere glass 9 , due to caging in the absence of polymers, to a second glass, stabilized by the short-range attractive depletion interactions, on increase of polymer concentration 13 . The two glasses could then be distinguished by the different plateau values in their intermediate scattering functions 3,4 and by their markedly difference rheological properties 14 .…”

“…The tunability of colloidal effective interactions 1 offers the possibility to observe unusual phase diagrams 2 including reentrant 3,4 or empty liquid 5,6 regimes, and multiple arrested states, such as gels 7,8 and glassy states 9,10 . Of particular interest are glass-glass transitions 3,4,11,12 , which are quite rare to be found, especially at ambient conditions. Normally, these are triggered by a modification of the effective interparticle interactions that is obtained though a change of external parameters.…”