Amorphous biomineral-reinforced hydrogels with dramatically enhanced toughness for strain sensing

Ionic conductive hydrogels are promising candidates for flexible wearable strain sensors and artificial skin. However, achieving high mechanical and sensing performance concurrently remains challenging. Herein, a novel biomineral-reinforced hydrogel composed of polyacrylamide (PAM) and highly stable amorphous calcium carbonate (ACC) is reported. Benefiting from the dual ionic doping strategy (Mg²⁺ and PO₄³⁻), ACC nanoparticles in hybrid hydrogels show a super stable amorphous nature. The resulting mineral hydrogel displays a high stretchability (>1150% strain), a dramatically enhanced fracture toughness (9.57±1.28 vs. 0.91±0.12 kJ m⁻²), and a desirable linear strain sensitivity. Moreover, the novel mineral hydrogel exhibits high biocompatibility and flame retardance, making it an appealing candidate for wearable device applications. © 2023 Elsevier B.V.