Fig. 2

Mechanical characteristics of multifunctional hydrogel. A Tensile stress–strain curves of the multifunctional PPGP hydrogel (PT-DA/PAA/rGO-PDA) with varying rGO-PDA concentrations. The inset displays a photograph of the hydrogel successfully supporting a substantial weight of 1 kg without disconnecting. B Fracture stress and toughness of multifunctional hydrogels as a function of rGO-PDA content. C Compressive stress–strain curves of the multifunctional hydrogel for different rGO-PDA concentrations. D Photographs illustrate the remarkable stretchability of the multifunctional hydrogel. E Photographs demonstrating the hydrogel’s exceptional mechanical recovery and resilience, even when subjected to highly concentrated stress from sharp objects such as tweezers (top) or a knife (bottom). F Photographs displaying the hydrogel’s high stretchability without fracturing, even under biaxial tension with an aerial strain exceeding 600%