Three-dimensional printers have brought major advances to every corner of manufacturing: Scientists have used the process to engineer human tissue, print a rubber material to make drones less dangerous to people on the ground, and create a lightweight material that's 10 times stronger than steel and just 1/20th its density.
Now, some of the coolest 3-D printing innovation is happening within the process itself. A team of MIT scientists has created a technique for 3-D printing objects that can transform after they're printed. Materials can change color, shape, size, and other physical and chemical properties.
According to a release from MIT, the objects are composed of special polymers that contain chemical groups known as TTCs. Each TTC acts "like a folded up accordion," which can be activated when exposed to blue LED light. New monomers or molecules then attach themselves to the polymers, giving the object new properties.
A soft object, then, could become stiff. The object's color could change, as could the way it reacts to water. Adding a certain monomer gives the objects the ability to expand or contract when exposed to certain temperatures.
"The idea is that you could print a material and subsequently take that material and, using light, morph the material into something else, or grow the material further," says Jeremiah Johnson, associate professor of chemistry at MIT and one of the team's researchers, in the release.
The process could open new doors for manufacturers, allowing them to easily create adaptable materials for use in fields like construction or medicine.
Researchers have experimented with similar methods in the past. Last year, scientists at Harvard unveiled so-called "4-D printing," a process by which 3-D printed objects change shape when submerged in water. (The fourth dimension, in this case, is time.)
The MIT team's new technique does have a key limitation: Due to the properties of the catalysts used, it requires an environment free of oxygen. The researchers are trying to refine the process so it can be used in an open-air setting.
The findings are outlined in a paper published in the January 13 issue of ACS Central Science.