A self-healing and energy-dissipating impact-hardening polymer based on a variety of reversible dynamic bonds

Modern protective materials must not only exhibit an intelligent response behavior, but also possess an excellent energy absorption ability. The applicability of shear-stiffening gel is limited because it generally cannot demonstrate good shape stability, strain sensitivity, and energy dissipation ability simultaneously. In this study, multiple hydrogen bonds and metal coordination bonds are incorporated into a shear-hardening gel to fabricate a new impact-hardening polymer (IHP-Cu) with multi-level energy dissipation pathways, thereby achieving a balance between shape stability, rapid self-healing, and energy dissipation. IHP-Cu maintains a stable shape in its natural state, exhibits significant strain-sensitive behavior at different strain rates, and supports a weight of 400 g at room temperature for 10 s after damage. In compression cycling tests, its energy absorption efficiency exceeded 90%. In the frequency-dependent test (strain rate of 0.1 s−1), its elastic work and viscous dissipation increased by 24 and 12.5 times, respectively, compared to those of the conventional shear-hardening gel. This paper also reveals the energy dissipation mechanism of IHP-Cu, thus providing a theoretical basis and reference for the development and optimization of new protective materials.