Under basic conditions, the model colloidal clay laponite�  forms a repulsive glass because of the strong electrostatic interactions. Addition of a non-adsorbing polymer, sodium polyacrylate, induces a depletion attraction.  Using light scattering techniques we experimentally show that for a given laponite�  concentration, addition of polymer results in the formation of laponite clusters. Increasing the concentration of polymer increases the strength of attraction between particles, resulting in an increase in the fast relaxation time (e.g., a decrease in short time diffusion). On the other hand, the structural arrest in such a suspension is entirely dependent on the cluster-cluster dynamics because of the hindrance in the diffusion of clusters. Depending upon the particle concentration, the resulting systems are either fluids of stable clusters or glasses of clusters.   To complement the light scattering results, rheological characterization of the suspensions has also been performed.

Polymer-mediated clustering of charged anisotropic colloids

244th National Meeting (2012)

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