A Dynamically Programmable Hydrogel Surface with Rapid Magnetically Actuated Snapping of Bistable Dome Configurations

Dynamic shape-morphing soft surfaces are widespread in biological systems and hold great promise for a variety of applications. Despite considerable efforts, challenges remain in achieving fast, repetitive, precise, and contactless control over the desired surface morphing. Here, this work presents a bio-inspired approach that leverages magnetically actuated dome snapping for fast and reprogrammable hydrogel surface morphing. The system consists of a sheet incorporating an array of swelled magnetic gels dispersed within nonswelling regions, forming bistable domes upon swelling. When a magnet approaches the side opposite to the bulking direction of a magnetic gel dome, the dome snaps rapidly toward the magnetic field due to direct magnetic interactions. By tailoring the magnetic threshold for the magnetic dome snapping, adjusting the spatial distribution of magnetic domes within the hydrogel, and precisely controlling the magnetic field, the hydrogel surface can dynamically morph in a programmable, ultrafast, and contactless manner. This work utilizes magnetically actuated surface morphing for dynamic displays, information encryption and decryption, and selective object manipulation. This work is expected to advance magnetically controlled soft robotics with multifunctional smart surfaces, unlocking a wide range of application possibilities.