The problem of stability of disperse systems is one of the key problems in colloid chemistry. This is due to the fact that most colloids are thermodynamically unstable, and their dispersed phase particles tend to aggregate. At the same time, the aggregation rate of many dispersed systems is small, and in this case a colloidal solution remains unchanged for a long time and thus can be considered kinetically stable (metastable). Unstable systems are exposed to coagulation leading to the formation of larger particles.

The stability of colloidal solutions varies in a very wide range: their life lasts from fractions of a second to hundreds of years. It depends on many factors: particles' size and concentration, process temperature, presence of electrolytes. In lyophobic systems, by adding electrolytes the coagulation rate increases sharply. At the same time, adding a lyophilic colloid to a lyophobic sol can slow down the coagulation process and make a kinetically stable colloidal system.