Extremely Compressible Hydrogel via Incorporation of Modified Graphitic Carbon Nitride

Extremely compressible hydrogels are fabricated in one pot via sulfonic‐acid‐modified graphitic carbon nitride (g‐CN‐AHPA) as a visible light photoinitiator and reinforcer. The hydrogels show unusual compressibility upon applied stress up to 12 MPa, presenting temporary physical deformation, and remain undamaged after stress removal despite their high water content (90 wt%). Cyclic compressibility proves the fatigue resistance of the covalently and electrostatically reinforced system that possesses tissue adhesive properties, shock resistance, cut resistance, and little to no toxicity. Surface‐functionalized carbon nitride facilitates the formation of extremely compressible hydrogels that withstand forces up to 12 MPa. In addition, the hydrogels feature tissue adhesive properties, shock resistance, cut resistance and little to no toxicity.