A team at the Wyss Institute and Harvard SEAS has developed a new microscale printing method to create transformable objects. These “4D-printed” objects go a step beyond 3D printing to incorporate a fourth dimension–time. The method was inspired by the way plants change shape over time in response to environmental stimuli. This orchid-shaped structure is printed with a hydrogel composite ink containing aligned cellulose fibrils, which enable anisotropic swelling. A proprietary mathematical model developed by the team precisely predicts how the fibrils will swell in water.
After printing, the 4D orchid is immersed in water to activate its shape transformation.