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:
η s c = [ η ] + k H [ η ] 2 c {\displaystyle {\frac {\eta _{s}}{c}}=[\eta ]+k_{H}[\eta ]^{2}c}
Where η s {\displaystyle {\eta _{s}}} is the specific viscosity of a solution at a given concentration of a polymer in solution, [ η ] {\displaystyle [\eta ]} is the intrinsic viscosity of the solution, k H {\displaystyle k_{H}} is the Huggins coefficient, and c {\displaystyle c} is the concentration of the polymer in solution. In isolation, n s {\displaystyle n_{s}} is the specific viscosity of a solution at a given concentration. The Huggins equation is valid when [ η ] c {\displaystyle [\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 ≈ 0.3 {\displaystyle k_{H}\approx 0.3} (for strong solvents) to k H ≈ 0.5 {\displaystyle 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, [ η ] {\displaystyle [\eta ]} , from experimental data by plotting η s c {\displaystyle {\frac {\eta _{s}}{c}}} versus the concentration of the solution, c {\displaystyle c} .
See also Viscosity Rheology
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