Characterisation of xanthan gum solutions using dynamic light scattering and rheology

Abstract

The `weak gel' formation mechanism of xanthan gum solutions has been examined using rheological and light scattering methods. Significant differences are observed between the critical overlap concentration (c*) measured using both techniques. The effect of shear on c* for semi-flexible molecules such as xanthan is demonstrated. The approximate theories of Doi and Edwards ((1984). The Theory of Polymer Dynamics. Oxford: Clarendon Press) for rigid rods and De Gennes ((1979). Scaling Concepts in Polymer Solutions. London: Cornell University Press) for random coils are used to explain the differences observed between rheological and light scattering measurements of c*. A second concentration reg..