This flat mesh automatically transforms into complex 3D shapes

A morphing printed mesh that transforms from flat sheets into 3D shapes could create new technology including soft robots, antennas and telescopes.

Created by researchers at MIT, Harvard, Boston University and Draper Laboratory, all in Massachusetts, the sheets transform in response to ambient temperature changes.

As a demonstration, the researchers printed a flat mesh that, when exposed to a certain temperature difference, deforms into the shape of a human face. They also designed a mesh embedded with conductive liquid metal, that curves into a dome to form an active antenna, the resonance frequency of which changes as it deforms.

In future, the researchers said the technique could be used for deployable structures such as tents or coverings. Other possibilities include stents or scaffolds for artificial tissue, or deformable lenses in telescopes. Mechanical engineer Wim van Rees said it could also be useful for soft robots.

“I'd like to see this incorporated in, for example, a robotic jellyfish that changes shape to swim as we put it in water,” said van Rees. “If you could use this as an actuator, like an artificial muscle, the actuator could be any arbitrary shape that transforms into another arbitrary shape. Then you're entering an entirely new design space in soft robotics.”

Morphing mesh

The creation process uses ‘inverse design’, starting with a complex 3D shape that the researchers want to achieve before asking how to programme the material. The structures are made of ‘ribs’, each consisting of four thinner ‘miniribs’ of rubbery PDMS infused with glass fibres. Each minirib is carefully calibrated to give a different response to temperature, offering different expansion or contraction, and they are arranged in such a way as to create different curves.

After printing the lattices, researchers cured them at 250ºC before placing them in saltwater baths and cooling them to room temperature. The meshes then morphed into their predetermined shapes, such as the face or antenna. The antenna was embedded with a liquid metal ink.

The team is now investigating ways of applying the method to stiffer materials for sturdier applications, such as tents and self-propelling fins and wings.

The research was published in the Proceedings of the National Academy of Sciences.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.