New techniques to advance '4D printing'

Scientists in Australia have said they are starting to develop techniques for 4D printing after having devised an autonomous valve.

Just as we’ve become accustomed with the process of 3D printing and its uses, researchers at the ARC Centre for Electromaterials Science (ACES) at the University of Wollongong in Australia have started to develop 3D printed materials that morph into new structures, under the influence of external stimuli such as water or heat.

ACES Professor Marc in het Panhuis told the BBC Today programme: “4D printing is a process, so there are no 4D printers. We use 3D printers to print 3D objects, which then transform into a different shape; very similar to what a child’s Transformer toy does.”

While in 3D printing a structure is built layer by layer, researchers envisage these new types of materials as able to transform themselves from one shape into another, in line with the fourth dimension – changing shape over time.

Panhuis’ team printed an autonomous valve, which can open and close itself without any help. They used a 3D printer where four materials were printed simultaneously that made the valve operational from the moment the printer finished, with no assembly required.

The materials, he said, possessed actuators that are activated solely by water. “So it's an autonomous valve, there's no input necessary other than water; it closes itself when it detects hot water.”

Although at this point efforts to define what 4D printing is are tentative, a handful of initiatives suggest that 4D printing takes smart materials form a 3D printer that can then assemble themselves. Another scientist who advocates shape shifting is Skylar Tibbits, a researcher in MIT’s architecture department.

The potential uses for 4D printing are extensive from extreme condition architecture to adaptive infrastructure such as pipes that expand and contract depending on water volume.

However, Panhuis hopes to take it further by developing 3D-printed materials to produce edible electronics that once in the body they unfold, perform a function and then disappear and biodegrade.

“You would sallow the capsule that would be made of something like gelatine; once the gelatine dissolves in your stomach a battery would start operating, without you having to do anything to it.

“That would activate a sensor and register everything that happens in your stomach, for instance. Once that function is done, it can disappear again.”

The ACES Chief Investigator said the ACES group was the first to combine printing a 4D device with four different cartridges simultaneously, while using tough gels with the incorporated actuating materials.

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