Advances in Impact Absorbing Shear Thickening Materials: A Comprehensive Review of STF and STG

Modern industries face challenges in impact resistance, energy absorption, and vibration damping, particularly in defence, aerospace, and automotive sectors. Conventional materials often fail under extreme conditions, necessitating innovative solutions. For such applications, non-Newtonian fluids, viz-a-viz Shear thickening materials (STMs), exhibit adaptive response to external forces, offering superior stability and resilience. This review explores advancements in STMs, focusing on shear-thickening fluids (STFs) and shear-thickening gels (STGs). STFs, composed of dispersed particles like silica in polyethylene glycol, enable energy absorption and impact resistance. STGs, with polymeric crosslinked networks and boron-oxygen bonding, overcome STF limitations including instability and sedimentation providing enhanced mechanical performance. STM finds applications in diverse industries. In defence, STMs enhance body armor, stab-resistant fabrics, and helmet liners by incorporating STMs in fiber-reinforced polymers. In aerospace and automotive sectors, they improve impact resistance and vibration damping. STMs enhance safety in sports gear and consumer products. Also, STF-based electrolytes improve lithium-ion battery safety. Despite their promise, challenges remain, including gaps in understanding shear thickening mechanisms under complex conditions. This review consolidates current knowledge, addressing these challenges and highlighting future research directions. By advancing the understanding of STMs, this work underscores their role in next-generation smart materials, fostering broader adoption in critical technologies.