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 qₘ change with time. We find that the intensity distributions scale according to S(q/qₘ,t)=qₘ(t)^-dF(q/qₘ), in agreement with the scaling law for spinodal decomposition. While d=3 for spinodal decomposition, here scaling requires that d=df, the fractal dimension of the clusters.