Comments on pattern formation in precipitation processes

We investigate the instability theory of spatial pattern formation in precipitating systems which focuses on post-nucleation phenomena in contrast to the supersaturation (prenucleation) theory of Ostwald. A scale analysis shows that very slow particle growth kinetics are necessary to match the experimental observations; this result rules out diffusion limited growth of colloidal particles. We further show that colloidal particle diffusion is quantitatively unimportant for the process of structure formation and does not provide a macroscopic length scale for diffusion limited growth kinetics.