14 DAY TRIAL // Rice University scientists have constructed the world's smallest car, a single molecule "nanocar" that contains a chassis, axles and four buckyball wheels.
The "nanocar" is described in a research paper that is available online and due to appear in an upcoming issue of the journal Nano Letters.
These single-molecule vehicles measure just 4x3 nanometers and have four buckyball wheels connected to four independently rotating axles and an organic chemical chassis.
The Rice team found that the nanocars moved about on a metal surface by rolling of the wheels in a direction perpendicular to the axles, rather than sliding about like a car on ice.
"The synthesis and testing of nanocars and other molecular machines is providing critical insight in our investigations of bottom-up molecular manufacturing," said one of the two lead researchers, James M. Tour, the Chao Professor of Chemistry, professor of mechanical engineering and materials science and professor of computer science. "We'd eventually like to move objects and do work in a controlled fashion on the molecular scale, and these vehicles are great test beds for that. They?re helping us learn the ground rules."
The nanocar consists of a chassis and axles made of well-defined organic groups with pivoting suspension and freely rotating axles. The wheels are buckyballs, spheres of pure carbon containing 60 atoms apiece. The entire car measures just 3-4 nanometers across, making it slightly wider than a strand of DNA. A human hair, by comparison, is about 80,000 nanometers in diameter.
Synthesis of the nanocars also produced major challenges. Tour's research group spent almost eight years perfecting the techniques used to make them. Much of the delay involved finding a way to attach the buckyball wheels without destroying the rest of the car. Palladium was used as a catalyst in the formation of the axle and chassis, and buckyballs had a tendency to shut down the palladium reactions, so finding the right method to attach the wheels involved a good bit of trial and error.