Recently published in Macromolecular Rapid Communications, the researchers at the University of Wollongong, Australia are adding a new dimension. Even though object printing (also known as 3D printing) only just began, this team has managed to build 3D printers that print objects that change their shape over time - what they are now calling 4D printing.
Regular 3D printers are pre-programmed to create structures layer by layer into a pre-programmed shape. Generally, some kind of plastic is used as the filament, whether recycled or not, but recently people have begun printing sugar and cellular material.
The researchers at UW have opted for tough hydrogels that can change their properties after being exposed to heat and moisture. Using hydrogel, the team has already printed a 3D smart valve that controls the flow of water; where cold water flows, and hot water closes the valve. Beyond the temperature of 35° C (95° F), the gel loses its water content and shrinks down to nearly 50% of the original volume, which stymies the flow of water. But as soon as the temperature drops, the shape retains the water and opens once again - all without any human intervention, and can repeatedly close and open without problems.
"The cool thing about it is that it's a working, functioning device that you just pick up from the printer," said one of the researchers, Marc in het Panhuis. "There's no other assembly required. It's an autonomous valve, there's no input necessary other than water."
Currently, the largest area that will benefit from this research will be the field of soft robotics, but eventually medicine, construction and even automation may benefit from this method.
Although it’s still in its early phase, it seems like the future is already half way here.