Abuzz with artificial iridescence

The beautiful rainbow sheen found on insect wings and exoskeletons arises from regular microscopic patterning of their reflective surfaces. Now, scientists in the US have developed a simple process to replicate and improve upon this phenomenon of iridescence.

The technique involves masking a surface with a preformed pattern of polymeric nanospheres that hexagonally pack together like balls in a snooker triangle. This pattern is then rapidly transferred onto the surface below using either plasma or reactive ion etching. The etched surface has structures similar to those found on the wings of many insects.

Altering the size of the nanospheres, the etching time and the surface material allowed the team at the University of North Carolina Greensboro to tune the resulting surface properties. As well as replicating the vibrant optical properties seen in nature, the team could change the way the surfaces interacted with water. This technique may enable scientists to design new materials to order.