In the past materials tended to remain static. More and more, researchers are developing dynamic materials that can change their shape on the fly.

One of the latest breakthroughs in this type of technology comes from researchers at Georgia Institute of Technology (Georgia Tech) and Ohio State University who have developed a magnetic shape memory polymer that can transform into a variety of shapes. Researchers believe the material can be used to create new capabilities in robotics and electronic applications.

shape memory polymer, robotics or electronics applications, Georgia Institute of Technology, Georgia Tech, Ohio State University
Researchers from the Georgia Institute of Technology (Georgia Tech) and The Ohio State University have developed a magnetic shape memory polymer that can transform into a variety of shapes, paving the way for new capabilities in robotics and electronics, they said. (Source: Georgia Tech)

The material—a mixture of three ingredients, each of which contribute unique properties that are integral to its behavior—uses magnetic fields to transform itself, said Jerry Qi, a professor of mechanical engineering at Georgia Tech.  The material is comprised of two types of magnetic particles—one that provides inductive heat and one with strong magnetic attraction—as well as shape-memory polymers that lock the shape changes in place, he said. This combination of materials is what provided researchers their unique result.

“This is the first material that combines the strengths of all of these individual components into a single system capable of rapid and reprogrammable shape changes that are lockable and reversible,” Qi said.

Creating freedom of movement

The new material builds on earlier research the team conducted that outlined actuation mechanisms for soft robotics and active materials, assessing the limitations in current technologies, said Ruike (Renee) Zhao, an assistant professor in the Department of Mechanical and Aerospace Engineering at Ohio State. “The degree of freedom is limited in conventional robotics,” she said. “With soft materials, that degree of freedom is unlimited.”

To create the material, researchers first distributed particles of neodymium iron boron and iron oxide into a mixture of shape memory polymers. Once the particles were fully integrated, they then create various objects from this mixture to test how the material would perform in various scenarios.

One example the team created to demonstrate their material was a gripper claw, which they fabricated from a t-shaped mold, researchers said. They applied a high-frequency, oscillating magnetic field to the gripper to cause the iron oxide particles to heat up through induction and warm the entire object. This rise in temperature than caused the material to soften, which made it pliable.

Researchers then applied a second magnetic field to the gripper to make its claws open and close, they said. Then, once the gripper cooled back down, whichever position it was in at the time remained locked.

Locking in the shape

The shape-changing process takes only a few seconds from start to finish, and the strength of the material at its locked state allowed the gripper to lift objects up to 1,000 times its own weight. “This process requires us to use of magnetic fields only during the actuation phase,” said Zhao. “So, once an object has reached its new shape, it can be locked there without constantly consuming energy.”

Researchers published a paper on their work in the journal Advanced Materials.

The team also tested other applications for the material, making coil-shaped objects that can expand and retract. This particular function simulates how an antenna could potentially change frequencies when actuated by the magnetic fields.

Other uses for the material are in robotics, Qi said, particularly for scenarios in which machines need to manipulate delicate objects, such as in the food industry or for chemical or biomedical applications.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.

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