Butterfly Wings Inspire Aussie Scientists to 3D Print Stronger Structures for the Future of Electronics

A sprig of this, a dose of that, and toss in some butterfly wings. While that may sound more like fairytale than scientific research, an important part of Callophrys Rubi’s anatomy may be the catalyst for a true breakthrough in the optics and photonics industries, areas which are continually improving upon themselves due to a competitive marketplace and constant customer demand.

One of the best stress relievers in the world is a dose of nature. It’s free, just outside your door. Fresh air, singing birds, and flitting butterflies are some of the most simple things that make our souls sing. Those moments of meditation can also be incredibly inspiring, as has been shown throughout the centuries, allowing many an invention to spring forth from the study of nature, often so complex and perfectly functional that it boggles the mind, while filling the heart too. Swinburne University of Technology researchers in Australia well understand this phenomenon, along with taking the concept of fragile, flying wings and making it their own, improving on it much like an open source software or hardware design we see so often today.

Why should we care? Because we like electronics—items like screens and displays—that’s why. And chances are, most of us enjoy them in as lightweight a form as possible. If you have ever lightly touched a butterfly, felt that silky wing, then this might all begin to make sense—as is it did for researchers who upon brainstorming headed off to start 3D printing gyroid structures faster than you can say ‘Green Hairstreak’ (the more common name known for this butterfly at hand).

Large-scale artificial gyroid PCs with different unit cell sizes showing good uniformity and mechanical strength.

Headed up by Dr. Zongsong Gan from Swinburne’s Centre for Micro-Photonics, the research had funding by:

• The Australian Research Council Centre for Ultrahigh-bandwidth Devices for Optical Systems
• The Laureate Fellowship scheme
• Science and Industry Endowment Fund under the John Stocker Postdoctoral Fellowship

While the idea already sounds plausible enough, certainly this amount of support and backing offers additional credibility to a study stemming from the insect world, which Gan and his team have outlined in ‘Biomimetic gyroid nanostructures exceeding their natural origins,’ recently published in Science Advances. They are busy proving that not only can they imitate nature—they can improve on it.

“These artificial structures are shown to have size, controllability, and uniformity that are superior to those of their biological counterparts,” state the researchers in their paper.

Seeing 3D printing as a highly relevant tool for ‘extracting 3D photonic designs from nature,’ the research team plans to use the technology for creating successful biomimetic nanostructures, taking advantage of how well the traditional gyroid structure works with light.

Using the form of the butterfly as a launching point in their discovery and consequent innovation, what they discovered was that while indeed it may be perfect in its natural state, it worked better for their purposes when scaled down, and thanks to their use of two-beam super-resolution lithography, they were able to do so. Regarding this technique, the researchers stated that it offers more flexibility in its artificial state in terms of cell size, filling fraction, and control of both orientation and termination.

Not just unique to this team, gyroid structures have been of growing interest also in the areas of:

• Photonic crystals
• Metamaterials
• Optical materials with topological complexity

Previous studies were limited though, as in the absence of 3D printing, the structures were created in forms much larger than an actual butterfly, and offered limited breakthrough therein.

“To fully replicate and exceed these 3D nanostructures, we need a 3D fabrication technique with a feature resolution of 100 nm and a feature separation of 300 nm,” state the researchers. “High-resolution lithography techniques, such as electron beam lithography, can give a resolution below 100 nm; however, it does not have intrinsic 3D capability. Multiphoton lithography is an ultimate approach to 3D nanofabrication, but lacks resolution below 100 nm.”

 

“Here, using optical two-beam super-resolution lithography, we demonstrate that this recently developed technique can fabricate biomimetic photonic structures with superior resolution, uniformity, and controllability.”

From the research study: Comparison of an artificial gyroid structure with a natural one. (A) Photograph of the butterfly C. rubi. (B) SEM image of the nanostructures found within the butterfly wings, with a periodicity of around 350 nm. (C) An artificial gyroid nanostructure fabricated by optical two-beam super-resolution lithography with a unit cell size of 360 nm. (D) Zoom-in of the artificial gyroid nanostructure. (E) White light reflection microscopy image of an artificial gyroid. Its lattice constant is 360 nm. The size of the structure is about 20 μm × 20 μm × 4 μm.

Ultimately, their goal was a structure that’s more durable and resilient and lightweight. As usual, we want it all—but often, 3D printing is capable of giving that; in fact, the research team was able to cash in on virtually every benefit the technology has to offer, taking a traditional design and improving on it with unprecedented customization in this field, along with enjoying the self-sustainability of creating and re-creating models in the lab, all the while creating greater speed and higher resolution, and undoubtedly affordability. The team’s particular 3D technique allows also for uniquely strong architectures, with accompanied high resolution. They did retain the striking blue-green color natural to the Green Hairstreak.

Even with a softer organic material, great mechanical, self-supporting strength was exhibited without structures relying on the natural struts found inside the natural butterfly.

“These new gyroid structures could help make more compact light based electronics because, thanks to their smaller size, larger numbers of devices can be integrated onto a single chip,” said Dr. Gan.

In comparison to what they were working with straight from nature, the 3D printing results show:

• Superior feature size
• Excellent feature resolution
• Long-range periodicity
• Well-defined crystalline boundaries

With the utilitarian functions being obvious in their designs, the team expects that this is just a beginning, operating as an initial breakthrough to leading to the future use of the gyroid shape in important applications regarding optics and photonics. Discuss further in the Butterfly Wings Inspire 3D Printed Optics forum over at 3DPB.com.