Growth laws and spinodal decomposition type of scaling in fractal aggregation of colloids

By means of extensive numerical simulations we have studied the time evolution and the scaling properties of the structure factor S(q,t) of diffusion-limited (DLCA) and reaction-limited (RLCA) colloid aggregation in three dimensions. We found that in DLCA S(q, t) scales in a similar way as in the spinodal decomposition process. The exponents a′ and a″ that relate the position and the height of the maximum of S(q, t) versus time, respectively, were however found to be different from those corresponding to the spinodal decomposition exponents. Unlike in the DLCA case, the S(q, t) for RLCA neither shows a pronounced maximum for the earlier times nor presents scaling. Nonetheless, the earlier broad peak eventually stretches and becomes higher than in DLCA.