Washington, Sep 25 (Inditop.com) Researchers have figured out how to produce a low cost shape-shifting “memory” foam, which could lead to more widespread applications in surgical positioning tools and valve mechanisms.
David Dunand, materials science professor at Northwestern University, has been collaborating with Peter M�llner, his counterpart at Boise State University, on a project focused on a nickel-manganese-gallium alloy that changes shape when exposed to a magnetic field.
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 as a result. This property could be an advantage in fast-operating actuators (mechanical devices for moving or controlling a mechanism or system) in ink jet 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, M�llner and colleagues have created polycrystalline foams that can be easily processed with shape-shifting properties resembling those of the much more expensive single crystals.
They did this by introducing small pores into the “nodes” of their original metallic foam, 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.
Northwestern and Boise State have jointly filed a patent application.
The results were published online in Nature Materials.
