On science
Parallel paths Designer Noora Yau and materials scientist Konrad Klockars have used wood to conjure up a colour, which is transparent yet glows like a copepod in shallow water. The pair’s good chemistry and open attitude towards asking silly questions is a great help in their work. Text: Minna Hölttä Photo: Jaakko Kahilaniemi
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s a child, Noora Yau was crazy about anything shiny and wondered why the watercolours sold at the store, even the golden ones, always looked so dull. Our experience of colour is determined by how our brains interpret the wavelengths of the light that hit our eyes. The majority of substances contain pigments or other colouring agents that reflect some wavelengths and absorb the rest. The reflected light is scattered randomly in all directions, making the colours matte and glossless. Many of nature’s most impressive colours are, however, created without pigments. A butterfly’s wings, a peacock’s feathers and the shell of a beetle are covered by a special nanostructure that gives them iridescent hues and makes them glisten in the sun. At Aalto University, Noora Yau and Konrad Klockars are working on their own, wood-based version of this nanostructure.
The subject was a good match
Their collaboration would probably not have started were it not for a fortunate failure and some coincidences. ‘When I applied for university studies, my first choice at Aalto was technical physics,’ Klockars says. ‘Now, I think it’s good that I didn’t get in – my math skills might not have been up to the standards required at Aalto. And my second choice, bioproduct technology, has proven to be much more interesting than I expected.’ For her part, Noora Yau’s Master’s studies had reached a point where it felt like the things she was designing were cool only for her, but not necessary for the world. Around this time, she was tasked with researching a new material as part of an industrial design course. 34 / AALTO UNIVERSITY MAGAZINE 27
One of the available subjects was structural colour. ‘It really clicked with me, although the only thing I knew about this subject was that it was somehow connected with butterfly wings. I learned about a copepod called sapphirina, a miniscule crustacean in which this effect is unbelievably powerful; viewed from one angle, it can appear entirely transparent or, when seen from another, it looks a very bright blue, like a little gem. I recalled how, as a child, I used to wonder what made things glitter, and the topic started to intrigue me more than I had thought possible.’ Yau needed help with her work, so she found her way to Professor Orlando Rojas, a specialist in new biomaterials, who welcomed Yau in his lab. During the first six months, Yau pored through a large pile of research papers, panicked slightly and then made small, confident steps forward in cooperation with postdoctoral researcher Maryam Borghei. And then Klockars, who was looking for an interesting thesis subject, got in contact with Orlando Rojas. ‘It sounded like a cool subject, and the opportunity to collaborate with a designer on something more than just technical problem solving was enticing.’
Renewable shine Humans can see light of wavelengths approximately between 400 and 700 nanometres. We perceive the shortest wavelengths as violet and then as blue, green, yellow, orange and red. Typically, the colours
we perceive are combinations of several wavelengths. However, the nanostructure leading to structural colouring lets all wavelengths through, apart from a single one. That wavelength reflects powerfully in one direction, just like from a mirror, and this is why structural colour is so bright and strong. Structural colour can also vary depending on the setting, as the angle it is viewed from determines what wavelength is reflected into our eyes. From some angles, it can reflect ultraviolet or infrared light that is invisible to the