Long-Time Dynamics of Concentrated Charge-Stabilized Colloids

Dynamic light scattering was used to study the dynamic structure factor, S(q, t), of suspensions of charged colloidal silica spheres over the full colloidal time range. We show that a dynamic scaling relation for S(q, t) found by Segre and Pusey [Phys. Rev. Lett. 77, 771 (1996)] for hard spheres, relating long-time and short-time dynamics, and collective and self-diffusion, also applies to charged colloids up to the freezing concentration. The universality of this scaling is analyzed theoretically. Our experimental data confirm dynamic freezing criteria proposed for the long-time self-and cage-diffusion coefficients, along with a theoretical prediction for the self-diffusion coefficient.