SPINODAL-TYPE DYNAMICS IN FRACTAL AGGREGATION OF COLLOIDAL CLUSTERS

The aggregation of dense colloidal solutions has been investigated by means of low-angle static light scattering. We show that the scattered pattern exhibits a finite-q-vector peak, whose intensity and position q(m) change with time. We find that the intensity distributions scale according to S(q/q(m),t) = q(m)(t)-d F(q/q(m)), in agreement with the scaling law for spinodal decomposition. While d = 3 for spinodal decomposition, here scaling requires that d = d(f), the fractal dimension of the clusters.