Dilute Solution Viscosity (DSV) is the viscosity measurement of dilute solutions of polymers. Typically, a sample is dissolved in a solvent at a specified concentration in the range 0.2 – 1.0 g/dl. Polymer solution viscosity is measured relative to the viscosity of the pure solvent.
Where η is the polymer solution viscosity and η0 is the viscosity of the pure solvent.
Traditional Glass Tubes Method of Measurement
With a traditional glass capillary tube viscometer, we measure the time it takes for the test liquid to flow through a capillary of a known diameter of a certain factor between 2 marked points.
By multiplying the time taken by the factor of the viscometer, the viscosity is obtained.
Determining Viscosity in this manner is both time-consuming and error-prone.
Glass capillary viscometers can not operate at very low concentrations and must therefore use several concentrations for a Huggins plot (see fig 2) to derive intrinsic viscosity by extrapolation to zero concentration.
The Relative Viscometer developed by Viscotek is able to operate at low concentrations and will give intrinsic viscosity from one sample run by use of the Solomon-Gatesman equation.
