Color outside the lines Mathias Kolle’s color changing material is derived from butterflies and molluscs. For Mathias Kolle, the wings of a butterfly are a window to a better material world. Insect iridescence is a result of “structural color” rather than color or dye: a wing is covered with hundreds of thousands of microscopic scales that act like small reflectors, bouncing light in different directions in depth, giving butterflies their characteristic color and shining.
Kolle, an assistant professor of mechanical engineering at MIT, delves into the microstructure of butterfly wings and other interesting materials in search of ways to replicate, or even improve, their effects twisted. He and his students are developing natural, high-performance optical materials, including color-changing paper and fibers that can be attached to pressure-monitoring bandages or attached to ropes exam the rainbow.
Just as butterflies display a wide range of colors without pigments or dyes, Kolle sees materials such as fabric, fiber, and water that can be created to create color without chemicals.
“If done properly, things can be made beautiful just by their composition, without adding any chemical pigments or dyes. “It’s exciting to look at so many amazing examples of color and shape and wonder how we can use the knowledge of nature’s way of playing with light to provide services for things in a way new.”
See the Light
Kolle was born and raised in Gera, a city in former East Germany, where his parents worked as pharmacists. In 1989, shortly after the fall of the Berlin Wall, he remembers entering West Germany for the first time.
“I am 7 years old; Our parents put me and my brother in our car to cross the border,” recalls Kolle. “Looking in the window of the toy store, I was blown away that the kids on the other side of the wall had things like Mickey Mouse and Matchbox cars.”
He returned from this trip with a souvenir: a simple crystal instrument, which sparked an interest in chemistry and science. Later, a high school teacher, Gunnar Pietzko, sparked Kolle’s interest in physics, with a demonstration of connected prisms and pendulums. After graduating, Kolle decided to study physics at the nearby Saarland University, which he chose for the opportunity to cross other borders. The university held a physics program in which students could divide their time between the Saarland and the University of Lorraine in France, and that year another option was added to study in Luxembourg, where Kolle wanted to explore.
During the five-year program, he and a few other students studied and traveled together between the three universities.
Kolle said: “We are the people of this united community that are united from nation to nation. “Every year, we start from scratch and go to another place we don’t know. I think it was a great learning experience.
During his studies, Kolle also trained in the Netherlands with Professor Ulli Steiner who allowed him to play with colors and materials.
“Ulli gave me a lot of freedom to do things. I was in his lab, mixing polymers and creating really interesting things, and I loved it,” said Kolle. “It was my first introduction to research using light processing. and exciting scientific research.”
Steiner moved to the University of Cambridge in Kolle, wanting to join his laboratory, he was encouraged to write a letter to support his doctoral work and a scholarship from the German Institute of Studies. Part of Steiner’s work was based on the use of polymers to create pigments, so Kolle relied on that theme when writing his designs.
“I have read a little about nanostructures that produce color without pigments and animals use this wonderful trick,” says Kolle. “I was surprised.”
After his proposal was accepted, he moved to Cambridge to begin doctoral work in physics, focusing on color composition. As part of his thesis, Kolle began to investigate the visual effects produced by scales on butterfly wings. He wondered: Can a synthetic material be made to imitate the wings of a butterfly? By the end of his doctorate, Kolle was able to carefully design a small, multi-faceted concave structure that resembled a small model of a butterfly.
He noticed that some specimens ranged from blue to green, like insect wings. Other samples, to his surprise, changed from red to blue – a much larger increase across the visible light spectrum that Kolle hadn’t expected. After some research, he found that these examples have an additional element of an unexpected element that was found to enhance the visual impact of the overall design.
“We have shown that there is a way to use synthetic materials to make these butterfly structures and – by default – you can improve there to do things that cannot be done physically,” Kolle explains. “It’s still a philosophy that I follow very strongly today.”
A prism of thought
After completing his doctorate, Kolle crossed the ocean to the other Cambridge, where thanks to a fellowship from the Humboldt Foundation, he worked as a postdoctoral fellow at Harvard University in the laboratory of Joanna Aizenberg, who was at the end of his career is high. engineering, inspired by the architecture and principles of nature. After three years in his group, Kolle applied for an open position in MIT’s engineering department.
“I enjoyed MIT,” says Kolle. “MIT’s can-do spirit is inspiring.”
In 2013, he was accepted as a junior teacher, and has already started a laboratory and a research program that reflects many different directions.
He and his students studied the microscopic structures that make up the different visual effects of butterflies and molluscs – work that involved his brother, a hydrologist. Using principles they find in nature, they have created new materials, such as photonic sheets and fibers that change color when deformed. They showed that these dyes could be incorporated into bandages and used as optical pressure sensors, to improve compression applied to the patient’s treated arm.
The team also explored the optics of individual water droplets and the ways in which individual droplets can act as miniature microscopes to magnify tiny features or create beautiful colors. With collaborators in England and Austria, they are trying to explain the relationship between genetics and biomechanics in the hearts of butterflies that can create colored nanostructures on their scales.
Kolle’s team also had a bit of fun with the optics. During a recent visit to his lab, students were experimenting with an exciting idea: They could make a red food that could be sprinkled in vinegar or ‘top of the cake to create an attractive visual effect and enhance the experience? Sharing this idea with others, Kolle said, is key to his team’s success.
“Many of the ideas I got at MIT turned out great because my students took them and figured out how to make them great,” Kolle said. “They saw the potential and took those ideas to heights I couldn’t imagine.”
Source: Massachusetts Institute of Technology
