Pluripotent Hydrogels With Ion-Tempered Mechanical Properties

Functional soft materials have a wide application prospect in many fields. However, these materials often have elaborately designed polymer network structures to generate unique performance for specific applications. In this work, we present a versatile strategy for adjusting the mechanical properties and thermoresponsive behaviors of hydrogels by ion-tempering, enabling their application in diverse scenarios. Thermoresponsive hydrogels with versatile applications are prepared by treating non-thermoresponsive poly(acrylic acid) (PAA) hydrogels with acetate solutions containing metal ions of Mg²⁺, Ca²⁺, Sr²⁺, Mn²⁺, Ni^2+, and Zn²⁺, respectively. Except for poly(acrylic acid)/ magnesium acetate (PAA/MgAc), all the other hydrogels exhibit thermo-induced phase separation behavior and shape memory properties with tunable hysteresis ratios. By exploiting the controllable recovery behavior of stretch-programmed hydrogels, the poly(acrylic acid)/ manganese acetate (PAA/MnAc) hydrogel could be applied as artificial muscles and generate effective contractile actuation. Furthermore, the strong ionic bonds within the poly(acrylic acid)/zinc acetate (PAA/ZnAc) hydrogel provide remarkable energy dissipation capability, rendering it ideal for damping and impact protection applications.