Devitrification of colloidal glasses in real space

Abstract

Confocal scanning laser microscopy has been used to quantitatively analyze the structure and dynamics of concentrated suspensions of spherical colloids in which the magnitude of the short-range attractive potential is increased by adding nonadsorbing polymers. These systems undergo a reentrant glass transition upon increasing polymer concentration. We find that melting of the glass is accompanied by significant changes in the displacement distribution and its moments. However, no significant variations have been detected in the shapes of the displacement distributions. Moreover, structural correlation functions and the magnitude of local density fluctuations do not vary significantly between the glass states and the fluid. Considering our experimental setup, these observations imply that local density fluctuations cannot be larger than a few percent of the average density.

Structural and Dynamical Features of Multiple Metastable Glassy States in a Colloidal System with Competing Interactions

“…It is a commonly held view that dynamical arrest is accompanied by little structural change. While literature on transitions between glassy states is scarce, the structural change in the attractive-repulsive glass transition at high packing fraction is rather subtle [27]. Conversely, all states identified here are characterized by their structures [see At higher c p , there is an increase in (cluster) size, yet our data suggest that it occurs rather gradually, i.e., passing from the Wigner to the cluster glassy state is a crossover rather than a sharp transition: particles start to form small clusters above a certain threshold c p and their size gradually increases with an increase in c p .…”

Tunable depletion potentials driven by shape variation of surfactant micelles

“…In contrast to most previous studies of the state diagram of colloidal glasses with attractive interparticle interactions [7][8][9][10][11][12], for example, the present system permits easy phase space exploration with the same sam- ple simply by changing temperature. In a different vein, the novel experimental method, along with a theoretical model for the interaction, offers a qualitatively new and effective means to extract information about the size and shape of depletant molecules at the nanoscale.…”

“…This attractive force is entropic in origin and is often called the depletion force [1,2]. Over the years, depletion forces have proved valuable as a means to control and study phase behavior [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], to direct self-assembly [19][20][21][22][23][24][25][26][27][28][29][30][31][32], and to control the stability of colloidal suspensions [33][34][35][36][37][38][39][40][41][42][43][44]. Depletion forces are also used in applications such as formulation and processing of food [45][46][47][48] and paint [49], and rel...…”

Dynamics in inhomogeneous liquids and glasses via the test particle limit

“…Recent measurements of G(r, t) using confocal microscopy were aimed at investigating e.g. dynamical heterogeneities in colloidal hard sphere suspensions [3], or the devitrification of colloidal glasses upon adding nonadsorbing polymers [4]. The Fourier transform of G(r, t), the intermediate scattering function, can be measured with inelastic scattering techniques [2].…”