Stiffer Than Steel

摘要

The ultralow-density ribbons described by Aliev et al on page 1575 of this issue (1) have the strength and stiffness of steel by weight in one direction and are more compliant than rubber in the other two. When charged, two dimensions quickly and reversibly triple in size while the third contracts. This response is virtually the same from liquid-nitrogen temperatures up to the melting point of iron. The ribbons are also transparent and flexible, yet conductive. The work is an exciting example of how nanostructuring can lead to combinations of properties that are not possible in bulk materials.rnNature provides the best examples of the power of nanostructuring. For example, human hair is as strong as some steels (much stronger when scaled by density), and unlike steel can be stretched by 30% before breaking.