Dynamic light scattering studies on the sol-gel transition of a suspension of anisotropic colloidal particles

We present a dynamic light scattering study on the sol-gel transition of a suspension of disk-shaped colloidal particles in water. We obtain the static and fluctuating part of the scattered intensity, the fraction of frozen-in density fluctuations, and the intermediate scattering function from a local time-averaged measurement of the intensity correlation function and the scattered intensity. The sol-gel transition is marked by a drastic change in the static part of the scattered intensity. The intermediate scattering function shows a stretching of the translational correlation time over more than five orders of magnitude. In the gel phase the function shows a power-law decay, with a concentration dependent scaling exponent. Our results show strong similarities with the scenarios given by the mode coupling theory of the structural glass transition.