Title of dissertation: Self-Assembled Photoresponsive and Thermoresponsive Nanostructures Kunshan Sun, Doctor of Philosophy, 2009 Diessertation directed by: Professor Srinivasa R. Raghavan, Department of Chemical and Biomolecular Engineering Responsive complex fluids based on nanostructures (e.g., micelles, vesicles and nanoparticles) have received considerable attention recently. The ability o...

We investigate the nonlinear rheological behavior of colloidal suspensions of Laponite, a synthetic clay, driven by steady homogeneous shear strain. We show that the external drive leads to drastic slowing down of the aging dynamics or even, in some cases, in rejuvenation of the system. Under shear, after a surprisingly long time, the spontaneous aging process observed at rest is suppressed. Th...

Small angle neutron scattering (SANS) data are reported from a system that models the contamination of a clay/organic matter soil from a fuel spillage. The soil was represented as an aqueous dispersion of the synthetic clay mineral Laponite coated with lysine, and the contaminant was a representative jet fuel, quadricyclane, mixed with the detergent cetyltrimethylammonium bromide (CTAB). The ad...

We investigate the time-dependent nonlinear optical absorption of a clay dispersion (Laponite) in an organic dye (rhodamine B) water solution displaying liquid-arrested state transition. Specifically, we determine the characteristic time tauD of the nonlinear susceptibility buildup due to the Soret effect. By comparing tauD with the relaxation time provided by standard dynamic light scattering ...

The efficiency of chiral bis(oxazoline)- and azabis(oxazoline)-copper complexes in the enantioselective carbene insertion into C-H bonds of cyclic ethers in homogeneous phase strongly depends on the structure of the substrate. The immobilization on laponite clay by electrostatic interactions not only allows the recovery and reuse of the heterogeneous catalysts, but in some cases also improves e...

The yielding behavior of a sheared Laponite suspension is investigated within a 1 mm gap under two different boundary conditions. No-slip conditions, ensured by using rough walls, lead to shear localization as already reported in various soft glassy materials. When apparent wall slip is allowed using a smooth geometry, the sample breaks up into macroscopic solid pieces that get slowly eroded by...