A
depletion force is an effective attractive force that arises between large
colloidal particles that are suspended in a dilute solution of
depletants, which are smaller solutes that are preferentially excluded from the vicinity of the large particles. One of the earliest reports of depletion forces that lead to particle coagulation is that of Bondy, who observed the separation or 'creaming' of rubber latex upon addition of polymer depletant molecules (sodium alginate) to solution. More generally, depletants can include
polymers,
micelles,
osmolytes, ink, mud, or paint dispersed in a .