Particle dynamics in concentrated colloidal suspensions

We have studied the dynamical and structural properties of dense charge stabilized colloidal suspensions by a combination of small-angle neutron scattering ( SANS), 3D dynamic light scattering (3DDLS) and diffusing wave spectroscopy (DWS). SANS and 3DDLS extend static and dynamic light scattering techniques to the regime of opaque samples while DWS additionally provides information on short length scales, typically from 1-50 nm. This offers an increased range of accessible length and time scales perfectly suited for the (non-invasive) investigation of highly concentrated suspensions. Different systems have been examined ranging from hard sphere like suspensions over strongly repulsive charged spheres to colloidal gels. We furthermore present an extended theoretical frame for DWS to characterize the internal dynamics of turbid gels made from nanosized colloidal particles.