Biomorphogenesis-Inspired Three-Dimensional Shape Transformation of Bilayer Polymer Sheets

Morphing a two-dimensional (2D) plate into customized three-dimensional (3D) structures with complex curvatures is of great importance for developing the next generation of soft robotics, flexible devices, and sensors. Yet, the practical application of shape-morphing materials remains challenging due to the material's inhomogeneous or discontinuous design. Herein, we demonstrate a biomorphogenesis-inspired paradigm that utilizes the ultraviolet mapping-based thickness gradient (UVM-TG) design for the shape transformation of bilayer-structured polymer sheets composed of a hydrogel layer and a hydrophobic polymer layer. The hydrophobic polymer layer as the passive layer is laser-engraved to create the thickness gradient distribution, which programs the dehydrative-shrinking-driven 3D shape transformation of the bilayer polymer sheets to deform into 3D structures with complex Gaussian curvatures, e.g., gourd and roadster. These 3D structures without uncontrollable surface buckling and wrinkles during those nonzero Gaussian curvature shape transformations exhibit reversible shaping/flattening switchability. Our UVM-TG design strategy, which does not require the inhomogeneous or discontinuous design of shape-morphing materials, establishes a facile strategy for fabricating shape-morphing materials.