Colloid (Gr. Collodes — Clay)

A colloid is a two-phase system in which particles of one phase ranging in size from 1 to 100 nm are distributed in another phase.

Colloid is also a gelatinous material secreted by the cells of the single-layer cuboidal epithelium of the thyroid gland. Colloids are characterized by high dispersion and a large total surface area of ​​the particles. Because of these properties, colloidal systems exhibit special optical, electrical, and diffusion properties.

Colloids are widely distributed in nature and have numerous applications in industry, medicine, food processing and other fields. The study of colloids is an important part of physical chemistry.