4D printing is unfolding as a technology that takes 3D printing to an entirely new level. Scientists at the University of Wollongong in Australia have created a hydrogel material that is compatible with a 3D printer that is able to change shape in response to water temperature.
The aim of “4D printing” is to extend additive manufacturing to the dimension of time. The idea is to create 3D-printed objects using special materials that are sensitive to heat, water or pressure that can change shape in response to environmental conditions, long after they’ve come out of the printer.
“According to Professor Marc in het Panhuis and team, current 4D printing applications can produce some very radical changes in shape, but they often take a long time to respond, the materials lose mechanical strength as they bend, and the shape-shifting is only reversible only up to a point. The scientists have therefore developed a special hydrogel that goes in a very different direction, generating quick, reversible and mechanically reliable changes in response to changes in water temperature.”
The unique structure of the 4D printing hydrogel toughens the material and prevents microscopic cracks from forming thus avoiding mechanical failures. Beyond a temperature of about 35° C, the gel quickly loses its water content and shrinks down in volume by nearly 50 percent. Researchers used this phenomenon to 3D-print a valve that closes when exposed to hot water and opens once water temperature drops. Unlike a standard 3D-printed material, the gel morphs without human intervention and can repeatedly open and close without straining. … (read more)