Encoding kirigami bi-materials to morph on target in response to temperature.

Shape morphing in response to an environmental stimulus, such as temperature, light, and chemical cues, is currently pursued in synthetic analogs for manifold applications in engineering, architecture, and beyond. Existing strategies mostly resort to active, namely smart or field responsive, materials, which undergo a change of their physical properties when subjected to an external stimulus. Their ability for shape morphing is intrinsic to the atomic/molecular structure as well as the mechanochemical interactions of their constituents. Programming shape changes with active materials require manipulation of their composition through chemical synthesis. Here, we demonstrate that a pair of off-the-shelf passive solids, such as wood and silicone rubber, can be topologically arranged in a kirigami bi-material to shape-morph on target in response to a temperature stimulus. A coherent framework is introduced to enable the optimal orchestration of bi-material units that can engage temperature to collectively deploy into a geometrically rich set of periodic and aperiodic shapes that can shape-match a predefined target. The results highlight reversible morphing by mechanics and geometry, thus contributing to relax the dependence of current strategies on material chemistry and fabrication.