Rheological characterization on novel viscoelastic tetrameric polyhydroxy cationic surfactant/sodium chloride micelle solutions

Abstract

A novel viscoelastic surfactant (VES) micelle system was developed by using a new tetrameric polyhydroxy cationic surfactant (STPC) as a thickener in combination with sodium chloride (NaCl). The flow curves, thixotropy, viscoelasticity, viscosity-temperature relationship, temperature and shear resistance, and thermal thixotropy of the micelle system were further investigated. The results showed that the new four-parameter rheo kinetic model accurately described the viscosity versus shear time curve of the micelle system. The established four-parameter viscosity-temperature relationship model could be used to characterize the viscosity versus temperature curve of the micelle system. Meanwhile, the Carreau model could also be fitted to the flow curve of the STPC/NaCl micelle solution. The effects of counterion salt concentration and surfactant concentration on the rheological properties of the viscoelastic STPC/NaCl micelle solution were clarified and the optimum mass ratio of 5 wt%/5 wt% for the STPC/NaCl solution was determined. The viscoelastic modulus versus temperature curves of the STPC/NaCl (5 wt%/5 wt%) micelle solution showed that it exhibited thermal thixotropy. This study extends on the types of thickeners and VES micelle systems and provides a rheological reference for the application of viscoelastic tetrameric cationic surfactants in oil fields.