specific surface (rus. поверхность, удельная otherwise удельная площадь поверхности) — characterisation of solidsemulsions and aerosols defined as the ratio of total surface area of a substance to its mass, or (more rarely) to the volume.


The specific surface of materials, depending on their dispersion and porosity ranges from a few to thousands of square metres per gram. Direct methods of determining the specific surface of solids are gas adsorption (in particular, BET method) and gas chromatography (for example, the method of thermal desorption). An indirect method is filtering a dilute gas, in which the surface area is estimated by the resistance experienced by the working gas passing through the layer of material or, more accurately, the magnitude of the effective Knudsen diffusion coefficient of the gas. Specific surface may be used to estimate the average size of powder particles or the average pore size of porous systems.


  • Gusev Alexander I.
  • Smirnov Andrey V.


  1. Gusev A. I. Nanomaterials, Nanostructures, and Nanotechnologies (in Russian) // Fizmatlit, Moscow (2007) - 416 pp.
  2. Gusev A. I., Rempel A. A. Nanocrystalline Materials. — Cambridge: Cambridge International Science Publishing, 2004. — 351 p.
  3. Manual of Symbols and Terminology for Physicochemical Quantities and Units. Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry // Pure Appl. Chem. 1972. V. 31. P. 577–638.

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