TEMPERATURE-DEPENDENCE OF VISCOSITY FOR SUCROSE LAURATE WATER MICELLAR SYSTEMS

The viscous behavior of sucrose laurate aqueous systems of high hydrop hilic-lipophilic balance up to a 50% (wt) surfactant concentration at temperatures between 5-degrees-C and 60-degrees-C has been studied. Sy stems up to a 45% (wt) surfactant concentration show Newtonian behavio r. The influence of temperature was studied using the activated diffus ive relaxation model described by Goodwin. A maximum specific viscosit y that appears at lower temperature as sucrose laurate concentration i ncreases can be observed. These results are related to the micellar gr owth of the sucrose laurate aggregates as temperature rises. More conc entrated systems show complex viscous response. Thus, a limit viscosit y at low shear rates and a shear-thinning behavior after a critical sh ear rate are observed. Limit viscosity decreases and critical shear ra te increases as temperature rises. This behavior is related to the thr eshold micelle concentration for entanglement of rod-like micelles.