Shimmering Wood – Experimenting with nanocellulose-based structural colour

Structural colour refers to the colouring that arises from the interaction of light with nanostructures. For example, the vivid, shiny, metallic-looking blue colour on the surface of morpho butterflies’ wing is created when light interacts with nanostructures, resulting in the perception of colour by the human eye. Shiny and glittery colour effects are linked to structural colours; however, they are often produced using materials made from metals, plastics, minerals or their combinations. The need for renewable, environmentally friendly colourants is growing, and in this context, the possibility of making bio-based structural colours has also received attention. This thesis researches nanocellulose-based structural colour (CNC SC) through the Shimmering Wood material development case. The project is an interdisciplinary collaboration between design and materials science. CNC SC has been studied since the 1990s, but the research has mainly focused on the colourant’s technical properties and applications, such as developing various optical sensors. Meanwhile, the aesthetics and appearance of the colourant have not received the same attention. In this thesis, CNC SC has been developed through collaboration between design and materials science, focusing on the aesthetics and appearance of CNC SC, as well as its potential as a future colourant for designers and artists. This collaboration aims to examine CNC SC comprehensively, considering both its technical features and sensory aspects, such as aesthetics and appearance. The main research questions of this study are: ‘What kind of material experiences can be designed for CNC SC?’ and ‘What new insights can design bring to the material development process? The thesis is based on three studies. The first study focused on framing relevant terminology for structural colours and introducing the topic to the realms of design and art. It also highlighted the problematic nature of the colour terminology related to structural colours, with particular attention being given to the term iridescence and its related issues. The second study detailed the practical process of the Shimmering Wood project and how new knowledge was constructed in the thesis by combining traditional materials science methods (such as laboratory work) with design methods (like material tinkering and prototyping). Lastly, the third study focused on developing the aesthetics of CNC SC in order to bring out the visual features that are characteristic of its colour appearance. The core findings of the dissertation involve making the terminology related to structural colour accessible to designers and artists, as well as introducing a more holistic perspective onto the material development process at a practical level. Introducing researchthrough-design methods into material development, particularly through the use of concrete design ‘things’, was found to facilitate interdisciplinary cooperation. These design ‘things’ were especially helpful in fostering interdisciplinary dialogue. In addition, CNC SC aesthetics and colour theory were framed in this study.