intrinsic viscosity (rus. характеристическая вязкость otherwise предельное число вязкости) — physical parameter which is determined by a change in the specific viscosity of a solution when a polymer is added.


The intrinsic viscosity is determined by:

where is the intrinsic viscosity, is the viscosity, is the viscosity of a solvent, is the polymer concentration in a solution (usually expressed in grams per 100 cm3). The intrinsic viscosity is determined by extrapolating the viscometry data to the zero polymer concentration. Units of measurement of the intrinsic viscosity are the inverse of the polymer concentration in a solution, cm3/g. The intrinsic viscosity is discussed for the extremely diluted solution, which assumes absolutely no polymer macromolecule interaction, and in the physical sense, it is a measure of additional energy losses in the flow of the solution due to the rotation and viscoelastic strain of macromolecules in the flow. The intrinsic viscosity is traditionally measured to determine the polymer molecular weight M, since they are related by the Mark-Houwink ,  where and are the empirical constants controlled by the independent calibration for each polymer-solvent pair.

The intrinsic viscosity of the polymer solution depends on the type of polymer and the solvent and increases as the molecular weight of linear macromolecules goes up. The molecular weight measured in that way is called a viscous mean. The measurement of  ), i.e., whether the macromolecules do not overlap in the solution.


  • Khokhlov Alexey R.
  • Govorun Elena N.
  • Nazarov Victor G.


  1. Encyclopedia of polymers (in Russian) // Ed. by Kargin V.A. et al. — Мoscow: Sovetskaja ehnciklopedija, 1972–1977.

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