Nature uses controlled folding and unfolding mechanisms to produce versatile architectures ranging from proteins to plants. This talent triggered the interest of scientists in so-called “origami assembly methods”. Origami, the traditional Japanese paper art, is a folding technique to form elegant and complex three-dimensional objects from planar sheets of paper. In wet-folding origami, a modified approach, the paper is wetted to enhance its pliability, while still retaining sufficient handling strength.
Now, for the first time, Lewis and co-workers have realized a controlled folding mechanism that allows for the formation of mesoscale metallic and ceramic structures in practically any envisioned shape—from a cube to the famous origami crane (as you can see below!).
The novel technique combines direct-write assembly with a process similar to the wet-folding origami technique. First, planar lattices are produced by printing filamentary arrays composed of a colloidal ink. In the next step these sheets are folded in the wet state by controlling their drying kinetics. After thermal treatment, those metallic and ceramic structures are robust enough that even large overhanging features, such as the crane’s wings, are fully supported.
This low-cost, versatile fabrication approach provides a new avenue for patterning functional materials for myriad applications, and similar three-dimensional objects may find use as tissue engineering scaffolds, biomedical devices, or catalyst supports.