Derjaguin

Boris Vladimirovich Derjaguin (1907–1994) was a Soviet physicist and chemist who helped establish modern colloid and surface science. He conducted foundational theoretical and experimental work on the behavior of colloidal suspensions, thin liquid films, and wetting phenomena, with long-standing impact on materials science and physical chemistry.

One of his major contributions is the DLVO theory, developed with Landau, Verwey, and Overbeek, which explains the stability of colloidal dispersions as a balance between attractive van der Waals forces and electrostatic repulsion due to the electrical double layer. The theory remains a standard framework in colloid science and has wide-ranging applications in coatings, mineral processing, and biology.

Derjaguin also formulated the Derjaguin approximation, a practical method for estimating forces between curved surfaces by relating them to plane-plane interactions. This approximation greatly simplified calculations in adhesion, colloid stability, and contact mechanics, and it is widely used in experiments and modeling involving spheres, fibers, and other curved geometries.

Another important concept associated with his work is the disjoining pressure in thin liquid films, which describes how film thickness and surface forces determine stability and rupture. This concept has influenced studies of wetting, dewetting, and capillarity in a variety of systems.

Derjaguin helped establish a strong scientific tradition in the USSR for colloid and interface science, influencing generations of researchers and contributing to international collaboration in physical chemistry and surface science.