Drifting at sea, isolated on a space station, or stuck in a war zone, engineers trying to build new things or patch together a repair are often constrained by the materials they have at hand. But what if they had one single polymer that they could coax into anything from a rubber band-like material or a ball of silly putty to a flexible sheet of plastic or a stiff, molded device?
Researchers at the University of Chicago’s Pritzker School of Molecular Engineering have now developed such a material, which they call a “pluripotent plastic.” Like pluripotent stem cells which can give rise to any type of adult cell in the human body, their plastic, described in the journal Science, can take on many final forms.
“We believe, this is the first example of a synthetic material that exhibits pluripotent behavior,” said Stuart Rowan, the Barry L. MacLean Professor for Molecular Engineering Innovation and Enterprise and senior author of the new work. “We believe that it paves the way toward a different way of thinking material design.”
A reversible plastic
To develop the new material, Rowan worked with PME assistant professor Shrayesh Patel, graduate student Nicholas Boynton, and colleagues at Argonne National Laboratory, the U.S. Army Research Laboratory, NASA, and the National Institute for Standards and Technology (NIST).
The pluripotent material is made up of polymers containing “dynamic covalent bonds,” which can break and re-form reversibly. Heating the material only to low temperatures (around 140° Fahrenheit, or 60 °C) allows the formation of more bonds, resulting in stiff, high-strength materials at room temperature. These could be used to make plastic utensils, among other things.
However, heating to higher temperatures (around 230°F/110 °C) results in fewer bonds being formed and, in turn, a more soft, extensible material that can be used for instance, as a pressure-sensitive adhesive.