Konrad Klockars studied structural colors formed from nanocellulose crystals in her doctoral thesis at Aalto University. The research is based on an observation made in Canada in the 1990s, and also involves interdisciplinary collaboration with the designer Noora Yaun with.
Structural colors can be found in nature, for example in butterfly wings, peacock feathers, or the shell of a beetle – they have a nanostructure that makes the colors shimmer in the sun. Structural colors made from nanocellulose work in the same way.
"Nanocellulose can form a nanostructure on its own, which dries into a film or coating with bright, shimmering color effects in rainbow colors. Such a structural color layer can be added to various hard surfaces," says Klockars.
In his doctoral dissertation, he investigated how the nanostructure formation process can be influenced, how drying can be controlled to achieve specific color patterns, and how drying stresses that affect the durability of the coating can be avoided.
"There is a lot of research into this, but it has generally focused on technical applications, such as optical sensors or polarizers or composites utilizing nanostructures. Our approach has been a little different, namely, we have studied how this can be used for long-lasting decorative applications, i.e. as aesthetic coatings, for example in wall panels, furniture or in the interior design of public spaces. Such a coating could also be suitable for luxury packaging."
Currently, similar effectors are produced using pigments, the production of which is fraught with problems due to their toxicity, microplastics and the use of child labor. Nanocellulose would be a responsible, non-toxic and environmentally friendly alternative.
Structural colors made from nanocellulose crystals could potentially even be used in car paints in the future, but this still requires a lot of research.
"The coating transmits most of the light and only reflects certain wavelengths, so this could also create more beautiful solar cells, for example on building facades, without reducing their efficiency."
Together with Noora Yau, Klockars has studied more closely how the material works as a wood coating, and the results have been good.
Austria has wood expertise
In August, Klockars will leave for a year-long researcher exchange at the University of Natural Resources and Life Sciences in Vienna (BOKU), for which he received a PI PostDoc grant of 45.500 euros.
“We have noticed that the coating adheres better to the wood surface than to other materials. We have qualitative data on this, but my intention in Austria is to study the interface between the coating and the wood in more detail and find out why this is the case.”
In addition, the research includes various durability tests – how the coating withstands, for example, washing, abrasion and various humidity fluctuations.
“The plan is also to find environmentally friendly ways to improve the moisture resistance of the coating.”
BOKU University in Vienna was selected as the exchange destination because it had the most suitable research group.
“Because of my family, I preferred to go to a European university, and I looked to see where I could find the most wood expertise. Professor Wolfgang Gindl Altmutter's The research group in Vienna seemed the most suitable, especially when it turned out that his group also had nanocellulose expertise.”
Konrad Klockars currently works in Otaniemi for a growth company that manufactures microcrystalline cellulose. Although he enjoys his current job, he is itching to get back to his own research.
“I am really grateful to PI for this grant,” he says.
