Layering and packing in confined colloidal suspensions.

Confinement modifies the properties of a fluid. The particle density is no longer uniform but depends on the distance from the walls; parallel to the walls, layers with different particle densities form. This affects the particle packing in the layers.

Characterization of slow dynamics in turbid colloidal systems by a cross-correlation scheme based on echo dynamic light scattering.

We describe the implementation of echo dynamic light scattering in a cross-correlation detection scheme, which enables the study of slow dynamics in moderately turbid colloidal systems by adapting a commercial light scattering device. Our setup combines a 3D cross-correlation detection scheme (3DDLS), which allows for suppression of multiple scattering, with the speckle echo technique for dynamic light scattering. The recorded cross-correlation echoes provide precise ensemble-averaged results that appropriately describe sample dynamics of ergodic and non-ergodic colloidal systems of different turbidities.