That’s what a team of researchers at the University of North Carolina at Chapel Hill and the University of Akron describe in a new paper, published in the journal Nature Communications. The paper details the invention of materials that can be programmed to change shape at a specific time, without the need for an external stimuli like heat or light.
“There are already a lot of materials which will respond to specific conditions, such as ice which converts to water at a certain temperature,” professor Sergei Sheiko, one of the paper’s co-authors, told Digital Trends. “The problem is that there are many systems, such as the human body, which remain very stable in terms of temperature, light, and other prompts that could act a stimulus to trigger change.”
That’s a problem if — as Sheiko and his collaborators are — you’re considering possible applications such as drug delivery inside the body. By shifting the trigger to a time-based one, it is therefore possible to create materials that will change shape on their own — controllable down to hours, minutes or even seconds.
The groundbreaking material is made using two different types of chemical bonds — dynamic and permanent — which control both the shape-shifting process and the final state of the material, once the change has taken place.
Sheiko said that there are plenty of possible applications for the work. “It might be possible to do minimally invasive surgery, in which a small, needle-like implant is inserted into the body, and can later change shape according to a timetable,” he said. Another use-case could be the creation of smart cement, programmed to set a specific time on a certain day.
For now, however, the most compelling demo the team has carried out is a shape-shifting flower because — come on! — who doesn’t want to see a shape-shifting flower?
“We wanted a demonstration that everyone would understand,” Sheiko explained. “We chose a flower because, in nature, it changes its shape as a function of time. We also liked it because it demonstrates that it’s possible to layer complex shapes — in this case, petals — that are programmed individually to open at different times. It shows that there aren’t limitations for our work in terms of shapes or designs.”
