Huggins equation

The Huggins Equation is an empirical equation used to relate the reduced viscosity of a dilute polymer solution to the concentration of the polymer in solution. It is named after Maurice L. Huggins. The Huggins equation states:

${\frac {\eta _{s}}{c}}=[\eta ]+k_{H}[\eta ]^{2}c$

Where ${\eta _{s}}$ is the specific viscosity of a solution at a given concentration of a polymer in solution, $[\eta ]$ is the intrinsic viscosity of the solution, $k_{H}$ is the Huggins coefficient, and $c$ is the concentration of the polymer in solution. In isolation, $n_{s}$ is the specific viscosity of a solution at a given concentration.

The Huggins equation is valid when $[\eta ]c$ is much smaller than 1, indicating that it is a dilute solution. The Huggins coefficient used in this equation is an indicator of the strength of a solvent. The coefficient typically ranges from about $0.3$ (for strong solvents) to $0.5$ (for poor solvents).

The Huggins equation is a useful tool because it can be used to determine the intrinsic viscosity, $[\eta ]$, from experimental data by plotting ${\frac {\eta _{s}}{c}}$versus the concentration of the solution, $c$.

See also

• Viscosity
• Rheology