Effect of multi-walled carbon nanotubes on linear viscoelastic behavior and microstructure of zwitterionic wormlike micelle at high temperature

Abstract

The effects of hydroxyl functionalized multi-walled carbon nanotubes (MWCNTs) on linear viscoelastic behavior and microstructure of zwitterionic surfactant oleylamido propyl betaine (BET) micellar solutions were investigated by Cryo-Transmission Electron Microscopy (Cryo-TEM), Fourier Transmission Infrared Spectroscopy (FT-IR) and rheological measurements. In this study, the addition of MWCNTs has obvious effects on the rheological behavior of the mixed system: an increase in the zero-shear viscosity of the system, and appearance of shear thinning non-Newtonian behavior instead of Newtonian behavior at dilute micellar solution. The addition of MWCNTs also obviously increases the semidilute micellar solution's relaxation time, reptation time and storage modulus. Moreover, the temperature resistance of the system with MWCNTs is greatly improved compared with that without MWCNTs. The results of Cryo-TEM and FT-IR measurement demonstrate that the MWCNTs can associate with wormlike micelle to form a strong and complex network structure by micellar end-cap adsorption and hydrogen bonding interaction. The synergistic interaction enhances the viscosity and elasticity of the zwitterionic surfactant fluids at high temperature.