Scientists at the Hebrew University of Jerusalem have created wood inks that can be extruded into flat wooden structures, which transform themselves into complex 3D shapes as they dry and shrink. The researchers presented their research at the American Chemical Society meeting in Chicago last week. The technique could one day be used to create furniture or other wooden products that can be shipped flat to a destination and then dried to achieve the desired final shape.
As we have reported before, developing new shape-shifting materials is a very active area of research because there are so many promising applications, such as building artificial muscles – man-made materials, actuators or similar devices that control the contraction, expansion and rotation (torque ) characteristics of the movement of natural muscles. The shape change occurs in response to an external stimulus.
For example, most artificial muscles are designed to respond to electric fields (such as electroactive polymers), temperature changes (such as shape memory alloys and fishing line), and changes in air pressure via pneumatics. In 2019, a team of Japanese researchers added a crystalline organic material to a polymer to make it more flexible, demonstrating their proof of concept by using their material to make a paper doll from aluminum foil sit-ups.
In 2020, MIT scientists successfully created flat structures that can transform into much more complicated structures, including a human face. These structures used the same fabrication technique as 3D printing, but are designed to deform over time in response to changes in humidity and temperature. They could one day be used to make tents that can self-unfold and inflate when temperatures or other environmental conditions change. Other potential applications include deformable telescope lenses, stents, artificial tissue scaffolds and soft robotics.
Last year, Luxo, Jr., Pixar’s signature animated balanced-arm Luxo lamp, helped inspire a new approach to building multifunctional shape-shifting materials for robotics, biotechnology and architectural applications. Physicists from Case Western Reserve University and Tufts University discovered how to remotely manipulate the normally flat surface of a liquid crystal without any kind of external stimulus (such as pressure or heat), changing its physical appearance only with the nearby presence of a bumpy surface . And scientists at Carnegie Mellon University created a simple mechanism to make flat pasta for shipping that takes on a specific 3D shape during cooking.
Typical manufacturing techniques treat materials such as wood as passive objects that must be actively formed. “You press it, you bend it, you cut it, you machine it, to get the shape you want,” Eran Sharon said at a press conference at the ACP meeting. “When you look at nature, nothing is made this way. Fabric expands gently and the shape comes from this distribution of different expansions and contractions. This is self-changing. We wanted to go back to the origins of this concept, to bring nature, and do it with wood.”