Disjoining pressure

In surface chemistry, disjoining pressure (symbol Πd) according to an IUPAC definition[1] arises from an attractive interaction between two surfaces. For two flat and parallel surfaces, the value of the disjoining pressure (i.e., the force per unit area) can be calculated as the derivative of the Gibbs energy of interaction per unit area in respect to distance (in the direction normal to that of the interacting surfaces). There is also a related concept of disjoining force, which can be viewed as disjoining pressure times the surface area of the interacting surfaces.

The concept of disjoining pressure was introduced by Derjaguin (1936) as the difference between the pressure in a region of a phase adjacent to a surface confining it, and the pressure in the bulk of this phase.[2][3]

  1. ^ ""Disjoining pressure". Entry in the IUPAC Compendium of Chemical Terminology ("The Gold Book"), the International Union of Pure and Applied Chemistry".
  2. ^ See:
    • Дерягин, Б. В. and Кусаков М. М. (Derjaguin, B. V. and Kusakov, M. M.) (1936) "Свойства тонких слоев жидкостей" (The properties of thin layers of liquids), Известия Академии Наук СССР, Серия Химическая (Proceedings of the Academy of Sciences of the USSR, Chemistry series), 5 : 741-753.
    • Derjaguin, B. with E. Obuchov (1936) "Anomalien dünner Flussigkeitsschichten. III. Ultramikrometrische Untersuchungen der Solvathüllen und des "elementaren" Quellungsaktes" (Anomalies of thin liquid layers. III. Investigations via ultramicroscope measurements of solvation shells and of the "elementary" act of imbibition), Acta Physicochimica U.R.S.S., 5 : 1-22.
  3. ^ A. Adamson, A. Gast, "Physical Chemistry of Surfaces", 6th edition, John Wiley and Sons Inc., 1997, page 247.