Multifunctional crystalline hydrogel with a multistage porous structure inspired by biomineralization and Ostwald ripening process: High elasticity, low hysteresis, and excellent sensing properties

[Display omitted] •Crystalline hydrogel with multistage porous structure has been rapidly synthesized by a one-step method.•Calcite crystals enhance the toughness and resilience of the hydrogel.•The hydrogel has excellent biocompatibility, frost resistance and flame retardancy.•The hydrogel can act as a sensor to detect physiological signals consistently and reliably.•SE-TENG can be utilized for powering electronic devices and tactile sensing. The advent of smart terminals has spurred interest in wearable epidermal electronic components composed of conductive hydrogels, with promising advancements in the real-time health monitoring, clinical diagnostics, medical care, and human–machine interaction sensing. However, despite their high sensitivity, conventional porous hydrogel materials often encounter challenges, such as non-uniform pore structures, inadequate energy dissipation mechanisms, structural instability, and poor fatigue resistance. Drawing inspiration from biomineralization and the Ostwald Ripening (OR) theory, this study rapidly synthesized an electron–ion synergistic P(AM-CO-AA)-PDMM crystalline hydrogel with a multistage pore structure via a one-step method (within 15 min). Additionally, the polydopamine-modified MXene (PDMM) enhanced the adhesion and antioxidant capabilities of the hydrogel. Upon subjecting amorphous calcium carbonate (ACC) to a high-temperature acidic copolymer network, it underwent CO2 gas release, resulting in a porous structure and transformation into stable calcite crystals uniformly dispersed within the hydrogel. The combination of rigid calcite crystals and a flexible hydrogel network confined network migration under slight strain and dissipated energy under larger strain. The resulting composite hydrogel demonstrated exceptional mechanical compressibility (compression hysteresis