adhesion
(rus. адгезия)
—
(from Latin "adhaesio" meaning linking) an attraction between different liquid or solid substances in molecular contact that cannot be broken without influence of external forces.
Description
Adhesion is a surface phenomenon that is typical of all disperse systems. Adhesion occurs at solid-solid, solid-liquid and liquid-liquid interfaces. Substances that come into contact are called substrates; substances that ensure the adhesion of substrates are called adhesives. Typically, substrates are solids (metals, polymers, glass, ceramics), adhesives are liquids (polymer solutions or melts, less often - low molecular weight products). Glue is an example of an adhesive.
Adhesion can be caused by: 1) mechanical adherence between phases (mechanical adhesion); 2) the formation of covalent or intermolecular bonds between the adhesive and the substrate (chemical or dispersive adhesion); 3) the formation of an electrical double layer (electrical adhesion) through charge transfer from one substrate to another. Mixed mechanisms of adhesion are also possible. Adhesive forces depend on the type and area of contacting surfaces and the surface properties of the substances. Adhesion occurs in the processes of friction, lubrication, powder metallurgy, flotation, etc., and in interactions between biological objects.
Adhesion can be caused by: 1) mechanical adherence between phases (mechanical adhesion); 2) the formation of covalent or intermolecular bonds between the adhesive and the substrate (chemical or dispersive adhesion); 3) the formation of an electrical double layer (electrical adhesion) through charge transfer from one substrate to another. Mixed mechanisms of adhesion are also possible. Adhesive forces depend on the type and area of contacting surfaces and the surface properties of the substances. Adhesion occurs in the processes of friction, lubrication, powder metallurgy, flotation, etc., and in interactions between biological objects.
Author
- Vadim V. Eremin
Sources
- Adhesion // Chemical encyclopedia (in Russian). V. 1. — Moscow: The Great Soviet Encyclopedia, 1998. p. 30–31.
- Zimon A. D. What is Adhesion? (in Russian). — Moscow: Nauka, 1983. — 176 pp.