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Ohio State, Georgia Tech collaboration creates shape-shifting material

Renee Zhao

  • Assistant Professor, Mechanical & Aerospace Engr

A team of researchers from The Ohio State University and the Georgia Institute of Technology has developed a soft polymer material, called magnetic shape memory polymer, that uses magnetic fields to transform into a variety of shapes. The material could enable a range of new applications in soft robotics, morphing structures and biomedical devices.

The material is a mixture of three different ingredients, all with unique characteristics: two types of magnetic particles—one for inductive heat and one with strong magnetic attraction—and shape-memory polymers to help lock various shape changes into place.

Led by Mechanical and Aerospace Engineering Assistant Professor Renee Zhao at Ohio State and Mechanical Engineering Professor Jerry Qi at Georgia Tech, the research is featured on the January 28, 2019, cover of the journal Advanced Materials. The National Science Foundation (NSF) supported the research through its Materials Research Science and Engineering Centers with an award to Ohio State.

The new material builds on earlier research that outlined actuation mechanisms for soft robotics and active materials and evaluated the limitations in current technologies. To make the material the researchers incorporated particles of neodymium iron boron (NdFeB) and iron oxide into a mixture of shape memory polymers, which they then molded into various objects designed to evaluate how the material performed in a series of applications.

At room temperature, the soft material is rigid. A high-frequency magnetic field is used to heat and cool the shape memory polymer to make it changeable and lock it into place, while a low-frequency magnetic field helps with multi-functional shape manipulation. 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.

Soft robotics is a subfield of robotics dealing with construction robots using material that can be controlled in very specific ways—often mimicking those found in living organisms. For example, the muscles that control an arm can be tighten, lengthen, and manipulated in a way that the user has complete control.

“The degree of freedom is limited in conventional robotics” Zhao said. “With soft materials, that degree of freedom is unlimited.”

The researchers also tested other applications, where coil-shaped objects made from the new material expanded and retracted—simulating how an antenna could potentially change frequencies when actuated by the magnetic fields.

“We envision this material being useful for situations where a robotic arm would need to lift a very delicate object without damaging it, such as in the food industry or for chemical or biomedical applications,” Georgia Tech's Qi said.

Dan Finotello, a program director at NSF added, "This polymer integrates fast reversible and reprogrammable actuation, shape locking and untethered operation for applications in soft robotics, morphing structures, and deformable electronics, especially for designing active and adaptive guidewires, catheters and stents that could potentially enable the next generation of biomedical devices for minimally invasive operations. It is a beautiful example of interdisciplinary research characterizing NSF's Materials Research Science and Engineering Centers program."

Zhao and Electrical and Computer Engineering Assistant Professor Liang Guo recently received a grant from the Juvenile Diabetes Research Foundation using similar technology to miniaturize an implantable insulin pump to work automatically within the body.

The collaborative research was supported by The Ohio State University Materials Research Seed Grant Program, funded by the National Science Foundation’s Center for Emergent Materials under grant No. DMR-1420451. The project was also supported by the Center for Exploration of Novel Complex Materials, the Institute for Materials Research, the Air Force Office of Scientific Research under grant No. FA9550-19-1-0151, the U.S. Department of Energy under grant No. DE-SC0001304, and by grants from the Haythornthwaite Foundation. The content is the responsibility of the authors and does not necessarily represent the official views of the sponsoring agencies.