Method to stack hundreds of nanoscale layers could open new vistas in materials science.
Adapting an old trick used for centuries by both metalsmiths and pastry makers, a team of researchers at MIT has found a way to efficiently create composite materials containing hundreds of layers that are just atoms thick but span the full width of the material. The discovery could open up wide-ranging possibilities for designing new, easy-to-manufacture composites for optical devices, electronic systems, and high-tech materials.
The work is described this week in a paper in Science by Michael Strano, the Carbon P. Dubbs Professor in Chemical Engineering; postdoc Pingwei Liu; and 11 other MIT students, postdocs, and professors.
Materials such as graphene, a two-dimensional form of pure carbon, and carbon nanotubes, tiny cylinders that are essentially rolled-up graphene, are “some of the strongest, hardest materials we have available,” says Strano, because their atoms are held together entirely by carbon-carbon bonds, which are “the strongest nature gives us” for chemical bonds to work with. So, researchers have been searching for ways of using these nanomaterials to add great strength to composite materials, much the way steel bars are used to reinforce concrete.
The biggest obstacle has been finding ways to embed these materials within a matrix of another material in an orderly way. These tiny sheets and tubes have a strong tendency to clump together, so just stirring them into a batch of liquid resin before it sets doesn’t work at all. The MIT team’s insight was in finding a way to create large numbers of layers, stacked in a perfectly orderly way, without having to stack each layer individually.