Patterning a surface with closely spaced nanometre-scale pillars can create structures that bend light, help to catalyse reactions and repel or attract fluids. But, typically, each variant pattern needs a new master mould, limiting scientists' ability to quickly test many possible patterns.
Joanna Aizenberg, Philseok Kim and their colleagues at Harvard University in Cambridge, Massachusetts, now show how to quickly transform a single master array into more complicated patterns. They deposit gold or platinum onto an array of nanopillars, and use the metal-covered posts as electrodes on which to deposit conducting polymers. By varying the deposition conditions, the researchers make tapered posts (pictured), overhangs and other three-dimensional structures with customizable diameters and spacings.