RHEOLOGICAL MASTER CURVES OF VISCOELASTIC SURFACTANT SOLUTIONS BY VARYING THE SOLVENT VISCOSITY AND TEMPERATURE

In this paper we present a study of the rheological properties of aque ous cetylpyridinium chloride/sodium salicylate solutions that have bee n measured as a function of both sucrose concentration and temperature . By using three different superposition methods we evaluated the rheo logical master curves for these solutions. In the low-frequency regime the rheological behavior can be described by a simple Maxwell materia l while in the high-frequency regime the sample is characterized by a Rouse-like behavior. Increasing the sucrose concentration causes some structural changes of the micelles to occur. In the Maxwellian part-of the spectrum we always obtain a uniform master curve independent-of t he amount of added sucrose and the temperature. Therefore in the limit of monoexponential stress relaxation a complete linear rheological de scription becomes possible by just knowing the relaxation time and the zero shear modulus of the solution. However, some deviations from thi s picture are observed in the regime of high frequencies and extremely high sucrose concentrations. Here we observe a Rouse-like spectrum an d structural changes in the elongated micelles due to the added sucros e.