AGGREGATION (Latin aggregatio — accession) — the association of particles of disperse and colloid (lyophobic) systems under the influence of molecular and intermolecular forces of an attraction leading to enlargement of particles. Process opposite And., call disaggregation. As a result And. there is an adhesion of separate particles with each other and formation of more difficult and large units, i.e. happens coagulation (see). Having reached a certain size, the last become incapable to keep in suspension and begin to be allocated from that environment where they were distributed — occurs sedimentation (see) a colloid. Speed And. depends on a charge and concentration of particles, structure of the environment, temperature, etc. Products And. depending on a form, distribution of charges and hydrations (see) can be loose or compact structure. Eventually in products And. there are processes of recrystallization, growth of more coarse particles due to dissolution of smaller, and And. becomes irreversible. For the prevention And. add shielding agents to lyophobic sols (the phenomena of protection and stabilization of sols — see. Sols , Colloids ). Phenomena And. matter during the studying of questions of stability of suspensions of medicinal substances and foodstuff, and also problems of structurization (gelation).
A. G. Pasynsky.