Tuning rheological performance of silica concentrated shear thickening fluid by using boric acid as additive.

Shear thickening fluid (STF) are non-Newtonian fluids that usually behave as liquid in normal condition however under sudden impact, they transformed into a solid like structure with abrupt rise in viscosity. The rheological properties of these fluids play a significant role in energy dissipation. In the present work, effect of boric acid (BA) as an additive for the fine tuning of shear thickening (ST) behavior of colloidal silica-based shear thickening fluids (STFs) was investigated. STFs were synthesized with silica particles (600 nm) in liquid polyethylene glycol (PEG-200). Both the steady state and dynamic rheological studies of STFs were carried out to compare ST behavior of BA based STFs with only silica-based STFs. In steady state rheology, it was observed that max. viscosity increases four time compared to only silica based STF. In dynamic rheology, it was observed that the maximum G′ and G″ of the STF composition (69% + 1.2% BA) at a frequency of 70 rad/s has increased by ∼41 times and ∼14 times, respectively, when the deforming strain reaches at 100% strain. Both the steady state and dynamic rheological analyses have confirmed that boric acid based STFs exhibited higher shear/strain thickening behavior, as well as higher energy absorption property. [ABSTRACT FROM AUTHOR]