LAUSR

Benefiting from the economic raw materials and efficient f abrication process, it is easy to directly scale up the hydrogels for biomedical scaffolds, functional materials, and storage systems. However, it remains challenging to construct stable hydrogel combining photoetching technology with low‐cost, room‐temperature, and low‐pressure fabrication. Here, a novel photoetching microcrystalline cellulose (M C C) @ Fe3O4/lignin‐Ca2+ hydrogel with excellent compressive strength (up to 300 kPa) is reported and its elasticity is well maintained under the temperature (−25–100 °C). Interestingly, the magnetic hydrogel exhibits controllable photoetching patterns based on the photothermal effect of Fe3O4 nanoparticles under near‐infrared irradiation (808 nm), especially in the different circumstances including enclosed space and underwater condition. In addition, the magnetic hydrogel displays the outstanding fire resistance and UV absorption (100%). The photoetching magnetic cellulose‐based hydrogel has great potential toward environmental‐friendly devices and applications in optics, electronics, sensors, and other miniature devices.