Probing the energy dissipation mechanisms of shear thickening gel at molecular level

Abstract

Shear thickening gels (STGs) exhibit remarkable impact resistance and energy absorption properties owing to the non-linear and reversible mechanical properties. However, the molecular-level mechanisms underlying their dissipation behavior remain unclear due to the limited understanding of how crosslinking density and local coordination influence energy redistribution and structural relaxation during impact. In this work, we developed a coarse-grained molecular dynamics model to investigate the impact induced energy conversion in STGs with different Si/B molar ratios. The simulations were validated by rheological experiments and accurately reproduced the nonlinear viscoelastic and shear thickening responses of system. The results show that energy evolution revealed a rapid transformation of kinetic energy into potential and internal deformation energy, followed by relaxation driven stabilization. Three coupled molecular processes-reversible coordination, chain conformational change, and orientational relaxation-were identified as key pathways that govern the dissipation efficiency and reversibility by regulating the partitioning of mechanical energy is partitioned between elastic storage, structural reconfiguration, and irreversible deformation. This work modulates the balance between elastic energy storage and irreversible deformation, thereby establishing a unified molecular framework that links network architecture to macroscopic impact performance.