Multifunctional nanostructures in the neck feathers of mallard

Drake feathers inspire multifunctional polymer crystals

The vivid colors observed in the plumage, carapaces and scales of birds, beetles and butterflies are certainly eye-catching, but the structures responsible are useful for more than a flamboyant display: Water repulsion, self-cleaning and sensory capacities have all been attributed to the nanoscale organization of structurally colored biomaterials. Guided by such evolution-driven design principles, UNAM (National Nanotechnology Research Center) researchers have recently engineered a multi-functional two-dimensional (2D) photonic crystal that functionally and structurally resembles the nanoarchitecture of mallard neck feathers, which effectively exhibit both a vivid green color and water-repelling properties. The article published in Nature family journal Scientific Reports.

Photonic crystals, ordered nanostructures that direct and alter the movement of light, hold great promise for a variety of engineering applications, but are difficult to produce as 2D surfaces. By repeatedly reducing the size of a large-scale preform through successive thermal drawing steps, Professor Mehmet Bayındır’s research group was able to produce polymeric 2D structures with aspect ratios and crystal parameters matching that of drake neck feathers, and to further demonstrate that the crystals in question matched their natural equivalents in both coloration and superhydrophobic behavior. Not limited to the characteristic green of drake feathers, the team was also able to manipulate the coloration exhibited by the nanomaterial, altering the lattice constant to create biomimetic photonic crystals of any desired color.

“We were very excited when we first looked at the electron microscopy images of feathers of the drake, yeşilbaşlı ördek. The feathers is indeed consisting of perfect 2D crystals which reflect only green light in the spectrum of sun. Interestingly, only male ducks exhibits such vivid green colors.” says Prof. Bayındır. Dr. Khudiyev, a postdoctoral associate in Bayindir research group, adds “Mallard feather is amazing multifunctional and nanoscale design illustration of nature. Besides the presence of unique structural arrangement that is responsible for reflection of bright green hue, outer surface of drake feathers exhibit wonderful water-repelling feature. We achieve to replicate both function and architecture with similar efficiency using our home-built fabrication method” says Dr. Khudiyev.

Combining the variability and adaptability of biological structures with the elasticity and pliability of polymer-based photonic materials, Dr. Bayındır’s feather-inspired photonic crystals may be utilized in applications where planar surfaces of light-interacting materials are required, such as the fabrication of color filters. The low-cost, iteratively driven fabrication method utilized by the team also lends itself well to the mass production of colored fabrics.

Their work is supported by the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013)/ERC Grant Agreement no. 307357 and TUBITAK under project no. 110M412.

Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes
T. Khudiyev, T. Dogan, and Mehmet Bayindir
Scientific Reports, volume 4, article number 4718 (2014)
[ Supplementary Information ]