Intrinsic viscosity

is (dynamic or kinematic) viscosity of the solution and

It should not be confused with inherent viscosity, which is the ratio of the natural logarithm of the relative viscosity to the mass concentration of the polymer.

When the solute particles are rigid spheres at infinite dilution, the intrinsic viscosity equals

is usually solute mass concentration (c, g/dL), and the units of intrinsic viscosity

are deciliters per gram (dL/g), otherwise known as inverse concentration.

Generalizing from spheres to spheroids with an axial semiaxis

, the intrinsic viscosity can be written where the constants are defined The

coefficients are the Jeffery functions It is possible to generalize the intrinsic viscosity formula from spheroids to arbitrary ellipsoids with semiaxes

The intrinsic viscosity formula may also be generalized to include a frequency dependence.

For example, the intrinsic viscosity can provide rough estimates of the number of subunits in a protein fiber composed of a helical array of proteins such as tubulin.

More generally, intrinsic viscosity can be used to assay quaternary structure.

In polymer chemistry intrinsic viscosity is related to molar mass through the Mark–Houwink equation.

A practical method for the determination of intrinsic viscosity is with a Ubbelohde viscometer or with a RheoSense VROC viscometer.