What Is 4-D Printing? Georgia Tech Researchers Demo Self-assembling Creations

Despite 3-D printers only now beginning to see real world use, scientists believe a new "4-D printer" holds the key to future structures.

Yesterday (March 21), a team of researchers from the Georgia Institute of Technology revealed their work on 4-D printing at the 255th National Meeting & Exposition of the American Chemical Society. The team was led by H. Jerry Qi, according to Science Daily.

4-D printing refers to the process of creating self-assembling structures that dynamically transform over time, reacting to environmental triggers such as heat, light and humidity. The objects are coded to remember different shapes that they transform into once the trigger begins. Think of it like a sunflower that opens its petals once the sun hits.

"We are on the cusp of creating a new generation of devices that could vastly expand the practical applications for 3-D and 4-D printing," Qi said. "Our prototype printer integrates many features that appear to simplify and expedite the processes used in traditional 3-D printing.

"As a result, we can use a variety of materials to create hard and soft components at the same time, incorporate conductivity wiring directly into shape-changing structures, and ultimately set the stage for the development of a host of 4-D products that could reshape the world."

The key substance in the process is shape memory polymers—the ink of the printer. Last year, Georgia Tech—with the help of the Singapore University of Technology and Design—managed to 4-D print a flower that could close its petals once a heat source was applied. They also printed a star that could bend itself into a dome in warm water.

4D printing
An object created by a team of researchers from Georgia Institute of Technology and two other institutions is suspended in water after permanently morphing from a flat to a curved shape in response to hot water. Rob Felt/Georgia Tech

The 4-D printer can even create electrical wiring. By using different materials in the same print, it can build entire electrical items, such as antennaes.

Qi and the team from Georgia believe the 4-D printer will have real world applications in aerospace engineering and medicine. They are already collaborating with Children's Healthcare of Atlanta to build prosthetic hands for physically disabled children.

"Only a small group of children have this condition, so there isn't a lot of commercial interest in it and must insurance does not cover the expense," Qi said. "But these children have a lot of challenges in their daily lives, and we hope our new 4-D printer will help them overcome some of these difficulties."