Dynamics of core-shell particles in concentrated suspensions

The dynamics of soft colloidal particles in a concentrated suspension was studied by two color dynamic light scattering. The short-time diffusion coefficient, D-s(q), revealed a weak slowing down around the peak of S(q) in contrast to the much stronger dependence observed in hard sphere systems, and the absence of any slowing down in ultrasoft diblock micelles. The low-q limit of the diffusion coefficient, D-s(q=0), reflecting the cooperative nature of the dynamics was found to decrease from its dilute limit value in contrast to the weak increase observed in hard sphere systems. The behavior of D-s(q) reflects distinct polymer-layer-induced hydrodynamic effects present in concentrated suspensions of core-shell particles.