Oscillatory Shear Measurements on Concentrated Dextran Solutions: Comparison with Doi and Edwards' Theory of Reptation

The Doi and Edwards' theory of reptation was tested in the linear region on the basis of oscillatory shear measurements for dextran solutions. Storage and loss moduli were measured as functions of frequency over the range 0.06–35 Hz and at 35.7 kHz, and polydispersity was measured using gel permeation chromatography. A modification of Doi and Edwards' theory, which takes into account the effects of molecular weight distribution, was used for comparison. Theoretical values assuming monodisperse polymer differed from the experimental values by more than 100%. The experimental results were found to be in good agreement with the modified theory. It was found possible to represent the results for both the solutions studied on one masterplot in terms of reduced variables.