Engineers discover nanoscale balancing act that mirrors forces at work in living systems
24 Aug 2011
A delicate balance of atomic forces can be exploited to make nanoparticle superclusters that are uniform in size - an attribute that's important for many nanotech applications but hard to accomplish, University of Michigan researchers say.
The same type of forces are at work bringing the building blocks of viruses together, and the inorganic supercluster structures in this research are in many ways similar to viruses.
U-M chemical engineering professors Nicholas Kotov and Sharon Glotzer led the research. The findings are newly published online in Nature Nanotechnology.
In another instance of forces behaving in unexpected ways at the nanoscale, they discovered that if you start with small nanoscale building blocks that are varied enough in size, the electrostatic repulsion force and van der Waals attraction force will balance each other and limit the growth of the clusters.
This equilibrium enables the formation of clusters that are uniform in size.
"The breakthrough here is that we've discovered a generic mechanism that causes these nanoparticles to assemble into near perfect structures," Glotzer said. "The physics that we see is not special to this system, and could be exploited with other materials. Now that we know how it works, we can design new building blocks that will assemble the same way."
