Programmable Material Mimics Life’s Flexibility

An experiment paves the way for the materials to be used in a range of fields, from health care to robotics

Professor looking at programmable fish in tank of water

This is a summary of a story that originally appeared on the Pratt School of Engineering.

Mechanical engineers at Duke University have made a breakthrough in programmable materials that can be assembled a bit like Lego blocks, only far more advanced.

Their new system allows solid structures to shift their mechanical properties on command, paving the way to creating robots that can adapt their stiffness and flexibility in real time to be used for a range of fields, from health to robotics.

The concept centers on hundreds of tiny cells filled with a gallium-iron composite. At room temperature, the material can be either solid or liquid. By using an electrical current to heat the material, researchers were able to liquify specific cells into any pattern they chose, effectively “writing” mechanical properties into the material.

“We want to make materials that are alive,” said Yun Bai, a Ph.D. student in the laboratory of Xiaoyue Ni, assistant professor of mechanical engineering and materials science at Duke.

Their work, published in Science Advances, marks a significant step toward materials that can be reprogrammed repeatedly.

To show how it works, the researchers built a robotic fish with a tail made from 10 Rubik’s cube-like connected blocks. Each block contained 27 programmable cells. By reprogramming the pattern of solid and liquid cells, the same motor produced different swimming paths for the robot fish. The experiment suggests future possibilities, from adaptive medical devices to robots that can move through tight or delicate spaces.

The team imagines miniaturized versions that could travel through blood vessels or reconfigure into stents. Looking ahead, Ni said their goal is to create flexible, programmable materials that enable robots to perform a wide range of tasks across many environments.

For more information, go to the Pratt School of Engineering.