"Bioreplication began about 2001 or 2002," said Akhlesh Lakhtakia, Godfrey Binder Professor of Engineering Science and Mechanics. "All the techniques currently available are not conducive to mass replications. In many cases you can make as many replicas as you want, but you need an insect for each replication. This is not good for industrial purposes."
The researchers chose blowfly eyes because they have potential application in the manufacture of solar cells. Blowflies have compound eyes that are roughly hemispherical; but within that half sphere, the surface is covered by macroscale hexagonal eyes with nanoscale features.
"These eyes are perfect for making solar cells because they would collect more sunlight from a larger area rather than just light that falls directly on a flat surface," said Lakhtakia.
However, in order to work in a manufactured product, the surface needs to retain the overall design in sufficient detail.
The researchers fixed the fly corneas on a glass substrate and filled the back of the corneas with polydimethylsiloxane, a silicone-based organic polymer, so that the metal covering they apply would not seep behind the eyes. They then deposited nickel on the surface using a modified form of the conformal-evaporated-film-by-rotation technique. In this technique, the researchers thermally evaporate the material that forms the coating in a vacuum chamber. The object receiving the coating is fixed to a holder and rotated about once every two seconds.
The researchers used arrays of nine blowfly eyes coated with 250 nanometers of nickel. This initial template was then electroformed -- a method of electroplating -- to deposit nickel on the back to create a master template half a millimeter thick. The thickness of the master template can be thicker.
"Polymer replicas produced . . . by casting did faithfully reproduce features of a few micrometers and larger in dimensions," the researchers reported in the online edition of Bioinspiration & Biomimetics.
The master template can be used either as a die to stamp the pattern or as a mold. The intention is to use the master die/mold to produce not only daughter dies/molds, but to tile the templates so that they can imprint large areas. The researchers will probably expand their template to include 30 blowfly corneas.
"One of the nice things about a conformal coating like this is, it becomes nanograined," said Lakhtakia. "The surface of the die becomes very smooth so the polymer will probably not stick."
Many biological surfaces exist that could create manufacture surfaces for a variety of applications. The researchers are currently looking at butterfly wings to understand how the surfaces create colors without pigment.
"Interestingly, the emerald ash borer, an insect that has recently become a problem in Pennsylvania, mates by color," said Lakhtakia. "Would lures made from templates of the ash borer skin attract males?"
The paper, "Mass Fabrication Technique For Polymeric Replicas Of Arrays Of Insect Corneas," Bioinspiration & Biomimetics is found at http://stacks.iop.org/1748-3190/5/036001.
A'ndrea Elyse Messer | EurekAlert!
What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society
Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy