Carbon Dot Bridging Effect Enables the Interweaving of Long‐ and Short‐Chain Polymers for Enhanced Hydrogel Performance

Abstract Amorphous polymer hydrogels have great potential applications in soft wearable systems, but designing for both strength and toughness remains a challenge. Although long chains and short chains can partially balance the contradiction between “rigidity and flexibility,” they usually achieve physical interweaving accompanied by structural instability. Herein, a novel strategy is proposed to construct the amorphous polymer hydrogel through the interweaving of long‐ and short‐chain via carbon dot bridging. Carbon dots grafted gelatin short chain are obtained by hydrothermal synthesis of 3,4‐dihydroxybenzaldehyde and gelatin (DGC). Flexible regions formed by carbon dots and polyacrylamide (PAM) long chains via hydrogen bonding, and rigid regions formed by carbon dots and gelatin short chains through Schiff base. Under stress, the hydrogen bonding can be broken, allowing the flexible regions to untangle and slip, whereas the rigid regions can effectively suppress the unrestricted slippage. This resulting DGC/PAM hydrogel achieves high modulus, high fracture toughness, and stable interfacial adhesion, exhibiting enhanced mechanical properties with a high tensile strength of 470 kPa, a toughness of 4.9 MJ·m −3 and a strain of 2200%, an excellent interfacial adhesion of 160 kPa. The proposed design strategy provides a facile approach to simultaneously improve cohesion and interfacial adhesion in amorphous polymer systems.