Programmable shape morphing of all-hydrogel-based sheet by acousto-photolithography

Shape-morphing hydrogels with stimuli-responsiveness have been extensively studied over decades due to non-contact control by external stimuli. One of the most common methods is to fabricate multilayer sheets with different materials to induce anisotropic volume changes. To date, however, combining swellable hydrogel layers with non-swellable layers results in issues with interface adhesion and structural integrity. Therefore, programming shapes of hydrogels by the spatial control of rigid particles to generate heterogeneous structures are in demand. Here, we develop the all-hydrogel-based actuators by integrating photothermal particles within the hydrogel matrix through acoustically driven particle assemblies to reach programmable shape deformation through temperature and light actuation. We anticipate this approach to program shape morphing in a single hydrogel sheet will open a new path for promising applications of composite hydrogels in the fields of biomimetic system, biomedical devices and soft robotics.