Researchers from Aalto University have achieved an innovative breakthrough by transforming waste wood into bio-based transparent films that can be used as anti-fogging or anti-reflective coatings on glasses or vehicle windows. This method not only offers an eco-friendly alternative to synthetic materials but also converts waste into a valuable carbon sink.

In the pulp and paper industry, lignin, due to its abundance and processing difficulties, is usually burned to generate heat. However, researchers have successfully developed lignin nanoparticles for anti-fogging coatings, which can also be transparent films.

The technique involves optimizing the esterification process of acetylated lignin, which requires only a few minutes at a relatively low temperature of 60°C. The resulting lignin nanoparticles possess unexpected properties, such as the ability to create photonic films. By adjusting the thickness and using multiple layers of films, researchers were able to generate materials with various structural colors.

Dr. Alexander Henn, the lead author of the study and a PhD student at Aalto University, emphasized the importance of collaboration in research. As a team effort, the project involved experts with diverse knowledge in lignin chemistry, photonic phenomena, techno-economic analysis, and more.

The viability assessment indicated that the esterification reaction is easy to perform and yields high results, suggesting that this method could be scaled up for industrial production. The creation of lignin-based products not only has potential for commercial value but also can contribute to carbon capture and reduce dependence on fossil fuels.

This innovative research was part of FinnCERES, the flagship center for bioeconomy materials research funded by the Academy of Finland. The study was published in Chemical Engineering.

Study reference:
Henn, K. A., et al. (2023) Transparent lignin nanoparticles for superhydrophilic antifogging coatings and photonic films. Chemical Engineering. doi:10.1016/j.cej.2023.145965