3D-Printed Material Moves In Response To Moisture

The use of 3D printers has helped us create objects or prototypes without the need for clay modeling or messing about with dangerous chemicals. Now, researchers at the University of Freiburg and University of Stuttgart have found a way to produce self-adjusting materials systems with the use of standard 3D-printers.

Previously, creating such material required the use of specialized printers and base materials that needed to be custom-made and were expensive to produce. But now, the researchers are able to create movable, self-adjusting materials systems with regular 3D-printers that anyone can buy off the shelf.

This is how it works according to the researchers:

They combined multiple swelling and stabilizing layers to realize a complex movement mechanism: a coiling structure that pulls tighter by unfolding ‘pockets’ as pressors and which can loosen up again on its own when the ‘pockets’ release and the coiled structure returns to the open state.

These printed materials undergo complex shape changes, enabling them to contract and expand when stimulated by moisture in a pre-programmed manner. The researchers modeled this approach based on the movement mechanism of the climbing plant, air potato (Dioscorea bulbifera).

Credit:Tiffany Cheng, ICD Universität Stuttgart

Mimicking this mechanism, they created a modular material system with layers that can bend in different directions and degrees, which enable them to coil to form a helix structure. ‘Pockets’ on the surface cause the helix to be pushed outward inducing tension on it. This in turn causes the entire system to contract. It could loosen again based on stimuli.

This material process has been collaboratively developed by:

Tiffany Cheng and Prof. Dr. Achim Menges from the Institute of Computational Design and Construction (ICD) and the Integrative Computational Design and Construction for Architecture Cluster of Excellence (IntCDC) at the University of Stuttgart, together with Prof. Dr. Thomas Speck from the Plant Biomechanics Group and the Living, Adaptive and Energy-autonomous Materials Systems Cluster of Excellence (livMatS) at the University of Freiburg.

“So far, our process is still limited to existing base materials that respond to moisture,” says Achim Menges. “We’re hoping,” Thomas Speck adds, “that in the future, inexpensive materials that also respond to other stimuli will become available for 3D-printing and can be used with our process.”

Through the new method, they were able to produce a prototype. It’s a forearm brace that adapts to the wearer. The new system has wide ranging medical applications. Instead of having a rigid, immobile system, they have one that can move about based on pre-programmed stimulus.