Effect of thermal surface activation of silica nanoparticles on the rheological behavior of shear thickening fluid

Abstract

Effect of thermal surface activation of silica nanoparticles on rheological behavior of shear thickening fluids (STF) was investigated. Silica nanoparticles of different particle size 250 nm, 500 nm and 600 nm were thermally activated at different temperatures 130 °C, 160 °C, & 190 °C for different time period of 2–6 h prior to STF synthesis. STF samples of activated and non activated silica nanoparticles were prepared in PEG-200 by sonochemical method and compared for their rheological behaviours. The results show positive and promising effect of heat activation of silica nanoparticles up to 160 °C temperature for enhancement of shear thickening behaviour in terms of maximum viscosity. Above 160 °C, STFs show decrease in maximum viscosity with increase in critical shear rate. These factors can be advantageous in development of high power STFs without use of any additive or surface modification of silica nanoparticles.