TEMPERATURE-DEPENDENCE OF VISCOSITY FOR SUCROSE LAURATE WATER MICELLAR SYSTEMS

The viscous behavior of sucrose laurate aqueous systems of high hydrophilic-lipophilic balance up to a 50% (wt) surfactant concentration at temperatures between 5-degrees-C and 60-degrees-C has been studied. Systems up to a 45% (wt) surfactant concentration show Newtonian behavior. The influence of temperature was studied using the activated diffusive relaxation model described by Goodwin. A maximum specific viscosity that appears at lower temperature as sucrose laurate concentration increases can be observed. These results are related to the micellar growth of the sucrose laurate aggregates as temperature rises. More concentrated systems show complex viscous response. Thus, a limit viscosity at low shear rates and a shear-thinning behavior after a critical shear rate are observed. Limit viscosity decreases and critical shear rate increases as temperature rises. This behavior is related to the threshold micelle concentration for entanglement of rod-like micelles.