Research in 4D Printing May Lead to Self-Assembly and Soft Robotics

Source: http://inside3dprinting.com/

(ExtremeTech) — The concept of 4D printing has begun to emerge. These 4D objects are still built layer by layer in a 3D printer. But given time, these devices can automatically morph into a different shape, and even change their function. Researchers have developed prototype devices using materials that are actuated by water or heat. Until now, the prototypes were slow, severely limited in the amount of times they could be used, and weak.

Professor Marc in het Panhuis and Ph.D. student Shannon Bakarich are working to eliminate — or at least diminish — 4D printing’s roadblocks. The University of Wollongong researchers used a process that printed four different materials simultaneously. The hydrogels used by the team consist of a network of poly N-isopropylacrylamide (PNIPAAm) and alginate. Alginate is a salt of alginic acid that is commonly found in seaweed and algae that is commonly used as a thickener in food. PNIPAAm consists of two polymer networks entangled in one another. This gives the material strength and durability. When cracks form in one network, the other network bridges the gaps and prevents greater damage. Using PNIAAm, the researchers have developed a functioning valve that responds to the temperature of the water surrounding it. “It’s an autonomous valve,” said Panhuis. “There’s no input necessary other than water. Maybe we will one day even be able to print our own self-assembling structures and soft robots.”