Intrinsic Viscosity

Intrinsic viscosity is a measure of a solute's contribution to the viscosity of a solution. Intrinsic viscosity is frequently referred to as "Inherent Viscosity" in macromolecular literature. It is defined as

$\left = \lim_{\phi \rightarrow 0} \frac{\eta - \eta_{0}}{\eta_{0}\phi}$

where is the viscosity in the absence of the solute and is the volume fraction of the solute in the solution. As defined here, the intrinsic viscosity is a dimensionless number. When the solute particles are rigid spheres, the intrinsic viscosity equals $\frac{5}{2}$ , as shown first by Albert Einstein.

In practical settings, φ is usually solute mass concentration, and the units of intrinsic viscosity are deciliters per gram (dL/g), otherwise known as inverse concentration.

Read more about Intrinsic Viscosity: Formulae For Rigid Spheroids, General Ellipsoidal Formulae, Frequency Dependence, Applications

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