Rheological behavior and microstructure of an anionic surfactant micelle solution with pyroelectric nanoparticle

The rheological behavior and microstructure of anionic fatty acid methyl ester sulfonate sodium (MES) surfactant micelle solution with pyroelectric nanoparticle were investigated by dynamic light scattering (DLS), freeze-fracture transmission electron microscopy (FF-TEM) and rheological measurement. The formation of wormlike micelle due to salt addition was observed and the nanoparticle can accelerate the micelle growth and entanglement with each other. The effect of concentration of surfactant, added salt and pyroelectric barium titanate (BaTiO3) nanoparticle were investigated, respectively. The viscosity of MES micelle solution increases with the temperature rise within a certain range because of the pyroelectric effect of nanoparticles. At low temperature (∼25 °C), the sample with 0.6 wt.% nanoparticle behaves like an elastic gel with an infinite relaxation time and viscosity. The change of microstructure and rheological properties for MES viscoelastic micelle solutions may be attributed to the electrostatic interaction and pseudo-crosslinking between micelles and nanoparticles. MES viscoelastic micelle solution can retain high viscosity at elevated temperature due to nanoparticle addition and has very attractive for reservoir stimulation and enhanced-oil-recovery in higher temperature reservoirs.