Smaller particles in a colloidal dispersion are less stable than larger ones due to their higher surface to volume ratio.
Therefore Ostwald ripening occurs, a process which promotes growth of larger particles at the expense of smaller ones (alternatively aggregation of smaller particles can occur).
In principle, this process goes on until one single particle is obtained.
Then, why are colloidal dispersions with lots of small particles stable? Or rather metastable? What makes the processes promoting further growth stop (ie dissolution of smaller particles in Ostwald ripening)? And do these processes really stop or just slow down tremendously?