Long range intercluster structural order has been observed in the late
, diffusion-limited stages of cluster-cluster aggregation of colloidal
monolayers at liquid surfaces. The structure factor S(q, t) scales as
q(m)-d(f)(t)F(q/q(m)), the exponent being the fractal dimension of tw
o dimensional diffusion-limited cluster aggregation. Such scaling is n
ot observed when the aggregation is reaction limited.