A central goal of our lab is to program shape into matter. Rather than sculpting a structure directly, we encode instructions for shape change into a flat sheet, which then autonomously transforms into a target three-dimensional geometry when exposed to the right stimulus.
Responsive gels were among the first materials to be used for shape-morphing structures. Their ability to reversibly and significantly change their equilibrium volume in response to a variety of external triggers makes them a good candidate for synthetic soft devices. The shape-morphing of these gels is achieved by spatially varying their chemical composition. We pursue this through several fabrication strategies.
We developed a novel 4D printing strategy for programmable materials (i.e. the additive manufacturing of responsive materials). Our approach is an extension of grayscale printing into 3D: we print hydrogels composed of two types of voxels (3D pixels) that have different responses to an external stimulus. The voxels are small enough that the discrete structure is smoothed by elasticity, analogous to how a black and white pixel map is smoothed to grayscale. These digital metamaterials can be encoded with an arbitrary geometry, providing precise control over the resulting shape and mechanical properties.
We developed a lithography apparatus in which a NIPAm gel is selectively cross-linked via exposure to UV. By irradiating the gel through grayscale masks, one can control the crosslinking density, hence programming the local shrinkage when the gel is heated. This system was used to build flat structures that morph into a variety of high-resolution 3D shapes such as spheres, saddles, and cones, as well as prescribing shrinkage fields corresponding to the geometry of dislocation defects. The resulting sheet buckled into 3D upon actuation, and cutting it in different orientations produced an emergent Burgers vector corresponding to the prescribed defect charge. This was an essential validation of the geometrical theory of defects.
Beyond hydrogels, we extend these strategies to elastomers, thermoplastics, and wood-based composites, broadening the palette of programmable materials.
I. Levin, E. Sachyani, R. Lieberman, N. Batat, E. Sharon, and S. Magdassi, 4D Printing of Fully Programmable Sheets of Digital Metamaterials Soft Matter, 2026, 22, 3312-3319
D. Kam, I. Levin, Y. Kutner, O. Lanciano, E. Sharon, O. Shoseyov, and S. Magdassi Wood Warping Composite by 3D Printing Polymers, 2022, 14 733
I. Levin, E. Siéfert, E. Sharon, and C. Maor, Hierarchy of Geometrical Frustration in Elastic Ribbons: shape-transitions and energy scaling obtained from a general asymptotic theory JMPS, 2021, 156 104579
E. Siéfert, I. Levin, and E. Sharon, Euclidean Frustrated Ribbons. Phys. Rev. X 2021 11
M. Moshe, I. Levin, H. Aharoni, R. Kupferman, and E. Sharon. Geometry and mechanics of two-dimensional defects in amorphous materials. PNAS. 2015 112(35)