472619 Clustering and Dynamics in Anisotropic Colloidal Glasses and Gels Containing Weakly Adsorbing Polymers

Wednesday, November 16, 2016: 10:15 AM
Union Square 23 & 24 (Hilton San Francisco Union Square)
Bingqian Zheng1, Suhasini Kishore2, Sunita Srivastava3 and Surita Bhatia1, (1)Department of Chemistry, Stony Brook University, Stony Brook, NY, (2)University of Massachusetts Amherst, Amherst, MA, (3)Stony Brook University, Stony Brook, NY

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.

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