Smart memory foam made smarter

September 24, 2009

Researchers from Northwestern University and Boise State University have figured out how to produce a less expensive shape-shifting "memory" foam, which could lead to more widespread applications of the material, such as in surgical positioning tools and valve mechanisms.

David Dunand, the James N. and Margie M. Krebs Professor of Materials Science and Engineering at Northwestern, has been collaborating with Peter Müllner, professor of materials science and engineering at Boise State, on a project focused on a nickel-manganese-gallium alloy that changes shape when exposed to a .

The alloy retains its new shape when the field is turned off but returns to its original shape if the field is rotated 90 degrees, demonstrating "magnetic shape-memory." The alloy can be activated millions of times, and it deforms reliably and reproducibly as a result. This property could be used to advantage in fast-operating actuators (mechanical devices for moving or controlling a mechanism or system) in inkjet printers, car engines and surgical tools.

To date, the magnetic shape-memory effect has occurred only in nickel-manganese-gallium single crystals, which are much more difficult and expensive to create than the more common polycrystals.

Now, Dunand, Müllner and their colleagues have created easily processable polycrystalline foams with shape-changing properties resembling those of the much more expensive single crystals. They did this by introducing small pores into the "nodes" of their original metallic , which, much like a sponge, consisted of struts connected by relatively large nodes. Adding a second level of porosity allowed for deformation and retention in the polycrystalline foam of some of the shape-memory properties.

The results are published online by the journal .

"One key aspect of this new 'smart' foam is that, together with a simple coil to produce a magnetic field, it creates a linear actuator of extreme simplicity -- and thus high reliability and miniaturization potential -- replacing a much more complex electro-mechanical system with many moving parts," Dunand said.

Potential applications range from replacing materials currently being used in sonar devices, precision actuators and magneto-mechanical sensors to enabling new devices in biomedicine and microrobotics.

"This was such a huge improvement that the foam was tested over and over again to make sure that no experimental mistakes were made," Müllner said. "Our new results may pave the way for magnetic shape-memory alloys for use in research labs and commercial applications."

Northwestern and Boise State have jointly filed a patent application.

More information: The title of the Nature Materials paper is "Giant Magnetic-field-induced Strains in Polycrystalline Ni-Mn-Ga Foams."

Source: Northwestern University (news : web)

Explore further: Precision control of movement in robots

Related Stories

Precision control of movement in robots

May 16, 2008

A research team from the Department of Electricity and Electronics at the University of the Basque Country’s Faculty of Science and Technology in Leioa, Spain, led by Victor Etxebarria, is investigating the characteristics ...

Recommended for you

Moonlighting molecules: Finding new uses for old enzymes

November 27, 2015

A collaboration between the University of Cambridge and MedImmune, the global biologics research and development arm of AstraZeneca, has led researchers to identify a potentially significant new application for a well-known ...

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...

Getting under the skin of a medieval mystery

November 23, 2015

A simple PVC eraser has helped an international team of scientists led by bioarchaeologists at the University of York to resolve the mystery surrounding the tissue-thin parchment used by medieval scribes to produce the first ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 25, 2009
Not the kind of memory foam I'd want in my mattress.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.