(458h) Clustering and Dynamics in Anisotropic Colloidal Glasses and Gels Containing Weakly Adsorbing Polymers

We report on large-scale structures and dynamics in an anisotropic colloidal system with weakly adsorbing polymers. Specifically, we utilize rheology, ultra-small angle neutron and x-ray scattering (USANS and USAXS), dynamic light scattering (DLS) and x-ray photon correlation spectroscopy (XPCS) to explore disk-shaped colloids, Laponite RD, in solution with polyethylene oxide (PEO). Aqueous dispersions of laponite form a repulsive colloidal glass. Nanometer to micron-sized aggregates form with the addition of PEO chains. DLS results indicate that, for lower laponite concentrations, these aggregates are stable in size and display diffusive behavior, suggesting that the fluids and solids we obtain are a liquid and glass of clusters, respectively. Through rheology, we observe the variations in the viscoelastic moduli (G' and G") which can be correlated with the changes in the low-q power law exponent extracted from an x-ray and neutron scattering experiment.