Design rules build on self-assembly

One of the challenges of making nanoscale patterns and structures is finding ways to control how particles as small as hundreds or tens of nanometers in diameter connect to each other. A nanometer is one millionth of a millimeter, or the width of 10 hydrogen atoms.

Researchers at the University of Michigan have developed computer simulations that show that adding sticky patches of molecules that connect to each other on a nanoparticle surface makes for building blocks that will self-assemble into a wide range of nanostructures, including chains, sheets, rings, shells, pyramids and staircases, depending on the position of the sticky patches.

The simulation provides design rules for building blocks that chemists and engineers can use to build nanostructures in the lab, and predicts which bottom-up assembly strategies will work and which will not, according to the researchers.

The simulation promises to speed the process of finding ways to build practical nanostructures, including precisely-structured materials, electronic and optical components, and chemical sensors. Quantum dots patterned with sticky molecular patches could be made to self-assemble into the wires and three-dimensional structures needed for quantum computer circuits, according to the researchers.

Many research teams have found ways to interconnect nanoparticles using molecules including DNA and proteins. The challenge in using the researchers' design rules is figuring out how to position the molecules on the particles.

Self-assemble arrays of patchy particles could be used in practical applications in two to five years, according to the researchers. The work appeared in the August 11, 2004 with issue of Nano Letters.