fig9

Figure 9. The anisotropic hydrogel actuator prepared by 3D printing. (A) Schematic of a 3D printed gradient-structured hydrogel and SEM images of its upper and lower surfaces; (B) Luminescent properties of this hydrogel. Reproduced with permission^[44]. Copyright 2022, Elsevier; (C) Schematic diagram of the shear arrangement of cellulose fibers during the 3D printing process and the deformation process of folded flowers with different printing paths. Reproduced with permission^[154]. Copyright 2016, Springer Nature Publishing Group; (D) The programmable deformation guided by printing technology. Reproduced with permission^[155]. Copyright 2022, Elsevier; (E) Schematic diagram of a 3D printed gel robot and the experimental displacements of the robots over three thermal stimulation cycles. Reproduced with permission^[159]. Copyright 2022, American Association for the Advancement of Science. 3D: Three-dimensional; SEM: scanning electron microscopy.