Light Management with Natural Materials: From Whiteness to Transparency

The possibility of structuring material at the nanoscale is essential to control light–matter interactions and therefore fabricate next‐generation paints and coatings. In this context, nature can serve not only as a source of inspiration for the design of such novel optical structures, but also as a primary source of materials. Here, some of the strategies used in nature to optimize light–matter interaction are reviewed and some of the recent progress in the production of optical materials made solely of plant‐derived building blocks is highlighted. In nature, nano‐ to micrometer‐sized structured materials made from biopolymers are at the origin of most of the light‐transport effects. How natural photonic systems manage light scattering and what can be learned from plants and animals to produce photonic materials from biopolymers are discussed. Tuning the light‐scattering properties via structural variations allows a wide range of appearances to be obtained, from whiteness to transparency, using the same renewable and biodegradable building blocks. Here, various transparent and white cellulose‐based materials produced so far are highlighted. A wide range of strategies is used to manage light propagation in plants and animals to produce transparent and white appearances. Inspired by nature, various transparent (low‐scattering) and opaque (high‐scattering) cellulose‐based materials have been developed. The possibility to structure materials at the nanoscale is essential to control light–matter interaction and enables the fabrication of next‐generation optical materials made of renewable biopolymers.