Synthesis and characterization of monodispersed silica‐based shear thickening fluid for impact resistance applications

Abstract Shear thickening fluid (STF), a highly concentrated mixture of nanosized silica particles in polyethylene glycol (PEG) is characterized by its quick transition to a stiff, solid‐like form under high shear rates. In this study, the modified Stöber synthesis approach was used for synthesizing the monodispersed spherical 300 nm silica nanoparticles. The rheological properties of the STF formulated using different silica loading were characterized. The Takshak model was tested to assess the rheological properties. The effect of the STFs on the impact resistance and yarn pull‐out force of the Kevlar® 802 fabric was determined. The uniformity in size of the silica nanoparticles facilitated more efficient packing within the fluid matrix, resulting in the formation of networks or structures that enhance shear thickening behavior. The STF with 70% silica exhibited the best peak viscosity of 45.8 Pa.s. Upon impregnation of this STF onto the Kevlar, a significantly high energy absorption (478.4%) compared to neat Kevlar, was observed. Moreover, the yarn pull‐out force for this system was found to be very high (435.8%). The reasons for the enhancement of the properties are explained. The novelty of this work lies in the synthesis of silica particles, analysis of the rheological properties, and interrelating the rheological properties with the characteristic parameters to define the impact characteristics. The improved properties underscore the suitability of synthesized STF for impact resistance applications.