Macromolecules, Vol.33, No.4, 1199-1205, 2000
A rheological and small-angle neutron scattering study of the structure of gelatin/polyelectrolyte complexes under shear
The small-angle neutron scattering and rheology of gelatin/polyanion complexes have been studied as a function of shear rate and ionic strength. It was found that the addition of very small amounts of sodium poly(styrene sulfonate) caused a massive increase in the viscosity of gelatin solutions through the formation of a complex between the two net negatively charged polymers. The scattering data showed a maximum in intensity at a specific value of the momentum transfer, reminiscent of the pattern produced by more concentrated pure polyelectrolyte solutions. At high shear rates the complex systems displayed anisotropic behavior: the scattering intensity at the peak was suppressed parallel to the direction of flow, indicating a change in the structure of the complex, but remained approximately constant perpendicular to the flow.