Double-layer temperature-sensitive hydrogel fabricated by 4D printing with fast shape deformation

Sensitive stimuli-responsive hydrogel has contributed much to the field of intelligent actuators. The ability to fabricate second-level response hydrogel has so far been elusive. Here, we fabricated a bilayer structure hydrogel by poly(NIPAM-co-DMAPMA)/clay composite hydrogel by 4D printing. The highest rate of angular velocity has reached 0.495 °/s. The initiated time is 1 s, and the whole deformation time is within 60 s. The quick response originates from the double-layer structure and the huge swelling ratio difference between the two-layer materials. And the grasping function of the palm provides a way to realize the multi-component 3D printing molding of various irregular-shaped thermal-responsive hydrogels, which is expected to promote the development and application of bionic simulation.