US researchers create 4-D printed objects

By Barry Eitel

SAN FRANCISCO

Scientists have created a three-dimensional printing method that creates objects that can permanently shift their shapes, an international team of researchers announced Wednesday.

The 4-D objects are formed from plastics that change shape in response to heat. In about five seconds, the printed objects can quickly bend, contort or expand. For example, one lattice-like structure could expand eight times its size when introduced to warm water.

Researchers have created shape-shifting 3-D printed objects before, but the objects were made from gels that were extremely soft. As a result, the objects required a very long time to change shape and would eventually revert to their original forms

The breakthrough is that the objects retain their new shape and change almost instantaneously when exposed to a heat source.

The 4-D printed objects could be used in medical devices, space exploration, robots and toys, according to researchers from Georgia Institute of Technology, Singapore University of Technology and Design and Xi’an Jiaotong University in China.

Products could be made that are flat for storage and shipping but then spring into a final shape once delivered. Medical implants could be built using the new method that change shape once in contact with body heat.

The project, which received funding from the U.S. Air Force and the National Science Foundation, was announced in the journal Science Advances.

“This new approach significantly simplifies and increases the potential of 4-D printing by incorporating the mechanical programming post-processing step directly into the 3-D printing process,” said study author Jerry Qi of Georgia Tech in a statement. “This allows high-resolution 3-D printed components to be designed by computer simulation, 3-D printed, and then directly and rapidly transformed into new permanent configurations by simply heating.”