The fourth dimension is time, shape shifting in fact, and the ARC Centre for Excellence for Electromaterials Science (ACES) at the University of Wollongong (UOW) is helping to set the pace in the next revolution in additive manufacturing.

With the extraordinary capabilities of 3D printing that have begun to infiltrate industry and the family home, researchers have started to develop 3D-printed materials that morph into new structures, post production, under the influence of external stimuli such as water or heat —hence the name, 4D printing.

As in 3D printing, a structure is built up layer by layer into the desired shape, but these new materials are able to transform themselves from one shape into another, such as a Transformer toy.

This science promises advancement in myriad fields —medicine, construction, automation and robotics, to name a few.

Another dimension: Prof. Marc in het Panhuis (left) and PhD student Shannon Bakarich are building objects using 4D printing, where time is the fourth dimension. Image Source: UOW.comACES researchers have turned their attention to the medical field of soft robotics, manufacturing a valve that actuates in response to its surrounding water's temperature.

ACES Professor Marc in het Panhuis says it was the cleverness of the valve's creation that was remarkable.

"The cool thing about it is it's a working functioning device that you just pick up from the printer," he says. "There's no other assembly required."

He says the valve, a 3D printed structure, possesses 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."

The work is published in Macromolecular Rapid Communications under the title “4D Printing with Mechanically Robust, Thermally Actuating Hydrogels” by authors Shannon Bakarich (PhD candidate), Doctor Robert Gorkin III, Professor Marc in het Panhuis and Professor Geoff Spinks .