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 $k_H\approx 0.3$ (for strong solvents) to $k_H\approx 0.5$ (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