Gold nanorods assemble themselves into rings
Rice University chemists have discovered that tiny building blocks known as gold nanorods spontaneously assemble themselves into ring-like superstructures. This could potentially lead to the development of novel nanodevices like highly sensitive optical sensors, superlenses, and even invisible objects for use in the military. They placed the nanorods in a solution of organic solvent called chloroform. As the chloroform evaporated, its surface temperature dropped low enough to cause condensation of water droplets from the air, much like how dew forms. As thousands and thousands of microdroplets of water formed on the surface of the liquid chloroform, the nanorods that had been suspended in the solution started to press up against the round droplets and form rings around them. The polymer coating prevented the rods from being absorbed into the droplets because it is insoluble in water.After the droplets evaporated, the nanorods remained in their ring formation. When nanorods are organized into a ring, significant changes in their optical and electromagnetic properties occur.
Source: physorg.comAdded: 26 March 2007