The Highlight effect in structural color from cellulose nanocrystals

Structural color arising from nanostructures of cellulose nanocrystals has been studied for some time already. However, well-founded practical applications for these visually enchanting colors have not been realized yet. The focus in the development of nanocellulose -based structural colors has been on advanced materials applications, for example, tunable reflective filters or various sensors. In contrast, our research aims to bring nanocellulose-based structural color into the fields of design and art.
There is a great need for eco-structural colors, as iridescent and glittering effect colors are commonly used in various visual industries. However, these colors are currently produced using environmentally harmful materials and toxic pigments. Cellulose nanocrystal structural color could potentially offer an alternative for these harmful colorants.
Cellulose nanocrystals (CNC) give rise to the so-called coffee ring effect (CR) when they assemble into the nanostructure responsible for the structural color. The effect refers to a rainbow-like border-color appearing on dry films. Scientists have generally considered this effect a problem to be solved since it prevents uniform color films. However, the same phenomenon could create visually and esthetically appealing effects. In the design and art field, this effect could be used as a "highlight-effect" since it can bring up the shapes and forms of the colored area. CNCs do this naturally, and as far as we know, no other coloring method can achieve this.
This conference paper is the first encounter with this phenomenon of coffee ring effect with structural colors that focuses on the effect’s visual properties. We present how the effect can be implemented into designs as a highlighter through prototypes and experiments. Methods used to execute this comes from research through design. Prototyping and experimenting with the material are used together with material science to discover the pattern making potential of CNC structural color.
We present design experiments in which the visuality of the CR effect has been utilized in design. By combining the open-minded methods of design with high-quality materials science, we can learn about the visuality of the material and possibly speed up the process that the new material requires to find its way to the use of designers and artists (and industry).