Self-assembly is a fundamental part of how things work in the universe. We often see it at the nano-scale, whether we're talking about nanotechnology or biochemistry. You put the right components together in the right context, and what results is a structure -- DNA, for example. Traditionally, the use of self-assembly to build nano-sized materials requires a lot of repetitive experimentation: try this set of components under these conditions; now slightly alter the setup and repeat, until you get what you want.
If researchers at Princeton University are right, though, the era of hit-or-miss self-assembly experiments may soon be over. A team led by Dr. Salvatore Torquato applied mathematical principles of optimization, which is essentially a process of finding the most efficient operation of a given process, to how components of a nanomaterial are organized prior to self-assembly. According to their computer models, this makes it possible to determine how to build a particular molecular structure before one starts, eliminating the need for repetitive sub-optimal experiments.
''If one thinks of a nanomaterial as a house, our approach enables a scientist to act as architect, contractor, and day laborer all wrapped up in one," Torquato said. "We design the components of the house, such as the 2-by-4s and cement blocks, so that they will interact with each other in such a way that when you throw them together randomly they self-assemble into the desired house."
To do the same thing using current techniques, by contrast, a scientist would have to conduct endless experiments to come up with the same house. And in the end that researcher may not end up with a house at all but rather metaphorically speaking -- with a garage or a horse stable or a grain silo.
Moreover, they may have stumbled across a easy way to make three-dimensional diamond lattices -- a material that some nanotechnologists have proposed as a fundamental building-block material for the nano-age.
So what does this all mean?
If the computer models work in reality, this would greatly accelerate the appearance of a fabrication form of nanotechnology, because it makes it easier to build what you want to build. It may not speed up the time needed to come up with the right tools, but once the assembly technology is possible, this would in principle let us jump to the "make stuff" phase, rather than linger in the "what can we make?" phase.
A brief version of the research was published in the November 25 Physical Review Letters; a longer version will appear later in Physical Review E.