3D-printed high-toughness double network hydrogels via digital light processing

Double-network hydrogels have attracted more and more attention in the field of hydrogels due to their high toughness and strength. Up to now, such hydrogels were processed only via model casting and extrusion-based three-dimensional (3D) printing, greatly restricting the freedom of design and manufacture. Herein, we provide a pre-hydrogel ink material composed of commercially available compounds, such as acrylamide and stearyl methacrylate, which can not only be suitable for vat photopolymerization, but also produces a hydrogel with double-network structures. Various hydrogel objects can be printed with a good CAD fidelity, verifying the good printability of the ink material. The printed hydrogels are based on an interpenetrated polymeric network consisting of covalent bond and hydrophobic association, enabling excellent toughness, puncture resistance, and self-recovering performance of the printed objects. The proposed approach may provide an effective way to design the ink of double-network hydrogels suitable for photocurable 3D printing, which may have great application prospects in the fields of customizing wearable sensors, robotics and biomedicine.