Synthetic molecules have visible hubs and spokes

Jul 9, 2007 07:33 GMT  ·  By
Scanning tunneling microscope images depict giant molecules with a diameter of 7 nm, whose "hub", "spokes", and "rim" are clearly recognizable.
   Scanning tunneling microscope images depict giant molecules with a diameter of 7 nm, whose "hub", "spokes", and "rim" are clearly recognizable.

No, the famous show "Pimp My Ride" hasn't moved from MTV to the nanoscale, but scientists have succeeded in producing the first nanoscale rims that look like the real deal. Though they are not likely to be mounted on miniature cars anytime soon, they will still find applications in nanocomposite materials.

Scientists from the University of Bonn, led by Sigurd H?ger, reported the first scanning tunneling microscope images showing 7 nanometers wide molecules, giants of the nanoworld that look like alloy rims, with clearly recognizable hub and spokes.

The unusual highly symmetric structures are actually inorganic alumina platelets, much like their round ancestors used in nanocomposites as fillers for plastics because they imbue these materials with excellent mechanical properties.

Thus, nanocomposites with embedded alumina platelets are extraordinarily rigid, strong and thermally stable, making an efficient barrier against gases and liquids. This impermeability could be used to create new food packaging and cheap environmentally friendly plastics.

It's the first time very large wheel-shaped molecules have been synthesized, starting from a star-shaped hub, to which rigid molecular building blocks were added, in the form of six spokes. In the end, all these parts of the flat molecule were connected to form a continuous rim.

Presenting many advantages, like the fact that they can be produced with uniform shapes and sizes, or that their chemical properties can be tuned to fit specific needs by adding functional groups, could mean that these alloy rims could soon find practical applications in many industrial areas, proving that they are not just a funny-looking science project.

The scientists won't stop here, as they now want to grow these rim-like structures even further by adding more and more building blocks onto the rim, thus creating new models, which they estimate to resemble spider web structures.