Investigating the effect of temperature, angular frequency, and strain on the rheological properties of shear thickening fluid (STF) with different weight fractions of fumed silica

Shear thickening fluids (STFs) have gained attention for their capacity to increase viscosity with higher shear rates, rendering them solid-like under high-impact conditions. This reversibility renders STFs valuable for diverse applications, particularly in defense systems. Preceding our study, mechanical hurdles, such as aggregation and blending issues, hindered efficient utilization. Our research presents an innovative method for STF synthesis using polyethylene glycol and SiO2 nanoparticles. Significantly, we employed a hot plate and oil bath to remove ethanol from the STF, a distinctive aspect of our approach. We also systematically explored the impact of temperature and the dispersion weight fraction of fumed silica nanoparticles on crucial rheological parameters, encompassing viscosity, shear rate, storage modulus (G '), and loss modulus (G ''). As temperatures increased, the critical shear rate also rose, while viscosity decreased. Additionally, we observed a significant enhancement in thickening behavior with higher SiO2 concentrations in STFs. For instance, the peak viscosity of 15 wt% STF decreased by approximately 69.47% from 20 to 40 degrees C and by approximately 89.92% from 20 to 60 degrees C. This study highlights the unique rheological properties of STFs.