Rheological properties of multi-walled carbon nanotubes/silica shear thickening fluid suspensions

In this study, the rheological properties of multi-walled carbon nanotubes/silica shear thickening fluid suspensions (MWCNT/SiO₂-STFs) with different concentrations were investigated. Through scanning electron microscopy, it was found that the MWCNTs had a strong adsorption on silica nanoparticles, and a "new particle group" containing MWCNTs was formed in the samples. The rheological results demonstrate that MWCNT/SiO₂-STFs have significant shear thinning and shear thickening phenomena, and when the mass fraction of MWCNTs is 0.8%, the STFs have the best shear thickening performance; the viscosity increases by 191% while the critical shear rate decreases by 60.19%. The results also reveal that the rheological property of MWCNT/SiO₂-STFs is effectively improved by increasing the plate spacing, particularly when their mass fraction is low. Moreover, the temperature sensitivity of MWCNT/SiO₂-STFs is still dominated by the silica nanoparticles. Without affecting their temperature sensitivity, the MWCNTs can significantly enhance the shear thickening performance of silica-based STFs.