With this Ring

Gold nanorodBishnu Khanal and Eugene Zubarev of Rice University in Houston, Texas have found that nanoscopic gold roads coated with polymer can spontaneously self-assemble into rings within seconds of water droplets condensing on to the surface of a solution of the rods in dichloromethane solvent.

Nanoscale objects organized into superstructures are interesting because the properties of such tiny particles depend not only on their composition, shape, and size, but also to a large extent on their spatial distribution and the degree of their ordering within a superstructure.

Images obtained with an electron microscope show that the nanorods in the rings are oriented randomly when their concentration in the original solution is high. However, at lower concentrations the result is truly amazing: The nanorods are oriented in a head-to-tail sequence along the edge of the ring.

The team reports details of their results in Angewandte