Effect of a hydrotrope on the viscoelastic properties of polymer-like micellar solutions

Abstract

Low-viscosity micellar aqueous solutions of cetyltrimethylammonium bromide (CTAB) undergo a major change in the presence of the hydrotrope, potassium 1-phenylmethylsulfate (KPhMS), producing a highly viscoelastic entanglement network of polymer-like micelles. The system studied here shows typical shear banding flow behavior, which tends to disappear with increasing the hydrotrope-to-surfactant concentration ratio (CH/CS). The linear rheological response was analyzed with the model of Granek-Cates, whereas the nonlinear behavior was reproduced with the Bautista-Manero-Puig (BMP) model. Both models introduce a kinetic equation to account for the breaking and reformation of the micelles, and they predict the linear and nonlinear rheological data very well. © Springer-Verlag 2007.