Shear-Stiffening Damping Ionogels Enabled by the Synergy of Dynamic Bonds and Steric Hindrance.

Abstract

High-rate impact loading causes structural failure and insufficient energy dissipation in protective materials. The intrinsic stiffness-damping trade-off in polymer materials makes it highly challenging to simultaneously achieve strong damping and broad frequency energy dissipation. Here, we developed tough ionogels with enhanced shear-stiffening and damping capabilities through the synergy of dynamic bonds and steric hindrance of hyperbranched polymeric ionic liquids (HPILs). The synergistic coupling of dynamic-bond dissociation in the high-frequency regime and the topological constraint of viscous-flow HPILs in the low-frequency regime endows the ionogels with broad-frequency damping and pronounced shear-stiffening behavior. The prepared ionogel shows an 842-fold shear-stiffening response and high damping (tan δ > 1) across a wide frequency range (10^- ³-10⁵ rad s^- ¹). At a high impact rate of 4000 s^- ¹, it also exhibits high impact strength (248.6 MPa) and toughness (86.5 MJ m^- ³). This strategy provides a reference for the design of next-generation high-performance damping ionogels.