The way a flower blooms or sways in a summer breeze has always been considered a kind of “divine” design. It has inspired poetry, art and now, even science. In nature, flowers and plants are able to change according to their environments thanks to their dynamic morphologies. Inspired by this natural process, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University created 4D-printed objects that change shape in response to their environment in the same way a plant does.
According to a press release, this novel way of printing should open doors in the fields of smart textiles, soft electronics, new biomedical devices and tissue engineering.
“This work represents an elegant advance in programmable materials assembly, made possible by a multidisciplinary approach,” said Jennifer A. Lewis, senior author of the new study. “We have now gone beyond integrating form and function to create transformable architectures.”
The team’s first endeavour sees the printing of two flowers of almost the same shape but different pre-programmed motions. The objects are placed in water to activate its pre-determined movements. The plant objects are created using a composite ink that flows like liquid through the printhead, but rapidly solidifies once printed.
The team is able to control the object’s behaviour using a mathematical approach. It is programmed to contain precise, localized swelling behaviours. The hydrogel composites contain cellulose fibrils that are derived from wood and are similar to the microstructures that enable shape changes in plants.
“It is wonderful to be able to design and realize, in an engineered structure, some of nature’s solutions,” says Core Faculty member at the Wyss Institute. L. Mahadevan.