Adhesion

Adhesion

ADHESION (from the Latin word "adhaesio", which means "sticking" * EN: adhesion, adherence; DE: Adhasion; FR: adhesion; ES: adhesion; RU: адгезия) the linkage of the heterogeneous solid bodies or liquid substances (phases), which are brought into the contact. It may be caused by both the intermolecular interaction and the chemical bond.

One of the most important characteristics of the adhesion is the adhesive strength, which is characterized by the specific force of the destruction of the adhesive contact, and is used in the technology in order to evaluate the properties of the glues, laquers, paints, etc. The adhesion strength depends on the energy of the bond, which provides the adhesion, on the completeness of the contact, which is determined by the relief of the surface, on the interphase surface energy, on the affinity to the liquids, and other surface phenomena, as well as on the conditions of the formation of the contact (pressure, temperature, duration, etc.). There are influencing the value of the strength the conditions of its measurement, the sizes of the samples, the concentration of the mechanical stresses in these samples. The destruction of adhesive contact may be accompanied by the destruction of the contacting bodies, because the adhesive strength is closely associated with the cohesion.

The adhesion of the liquid to the solid body is mainly determined by the values of the surface energy of the liquid, of the solid body, and the interphase surface energy. The adhesion is associated with the surface phenomena, but it can also determine the volume properties of the contacting bodies, in particular their structure in the zone of the contact, the distribution of the mechanical stresses in the field of the external forces, the kinetics of the relaxation processes. The adhesion causes the decisive influence on the mechanical properties of the composite materials. There are associated with it the gluing, coating, sintering, and many other practical important technological processes.