In a laboratory at Shenzhen University, a very thin coating reflects light in a fascinating way, changing hue depending on the angle. It is not a simple piece of plastic, but the fruit of years of research and inspiration from nature: a material that imitates the extraordinary ability of butterfly wings, capable of manipulating light.
Inspiration from nature
The farfalle Blue morpho (morpho menelaus) are extraordinary creatures. Their wings are covered in nanostructures that reflect and bend incoming light, producing a blue color that appears vivid and vibrant from many angles. Wanlin Wang and his team at ShenzhenUniversity they have not remained indifferent to this spectacle of nature.
They saw beyond the beauty and glimpsed a potential solution to a modern problem: how to keep our cars cool without sacrificing aesthetics?
A “butterfly wing” film
The team designed a thin coating that acts similar to reflective paints already present on the market. But there's one key difference: While traditional paints can lack vibrancy, this one offers a range of bright (and iridescent) colors that is nothing short of extraordinary.
The coating, only a few micrometres thick, consists of three layers. The former is a compound of titanium, silicon and oxygen. The underlying layers are a special opaque glass and a thin 'mirror' silver layer. This opaque glass is no ordinary glass: it has countless small structures that give it a “foggy” appearance, just like the blue Morpho butterfly wings.
Reflection, refraction and… cooling!
When a material absorbs light, its temperature increases. That's why, on a sunny day, the interior of a car can feel like an oven. Wang's team's idea was to design the layers of the film to diffuse light, creating a cooling effect. And they didn't stop there: they also discovered how to control reflection to change the color of the coating.
Imagine parking your car under the scorching sun. After a few hours, I would even be afraid to touch the steering wheel, so to speak. Well, during testing, Wang and his team found that all of the coating samples remained about 2°C cooler than the surrounding air. But the real magic emerged when they did tests directly on a car, comparing the butterfly wing coating to a plain blue film. Result? 75°C versus 42°C. A notable difference.
A bright and fresh future like butterfly wings
Wang is optimistic. He sees a future where this thin, colorful coating could coat electric vehicles, significantly reducing air conditioner energy consumption and increasing the vehicle's range.
Again, biomimicry shows us the way. I will never get tired of saying it, I'm crazy about it. The Blue Morpho Butterflies, with their bright, colorful wings, could hold the key to a future where our cars are not only cooler, but better looking too.
