Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
Nat Commun. 2022 Jun 13;13(1):3378. doi: 10.1038/s41467-022-31079-9.
When pursuing sustainable approaches to fabricate photonic structures, nature can be used as a source of inspiration for both the nanoarchitecture and the constituent materials. Although several biomaterials have been promised as suitable candidates for photonic materials and pigments, their fabrication processes have been limited to the small to medium-scale production of films. Here, by employing a substrate-free process, structurally coloured microparticles are produced via the confined self-assembly of a cholesteric cellulose nanocrystal (CNC) suspension within emulsified microdroplets. Upon drying, the droplets undergo multiple buckling events, which allow for greater contraction of the nanostructure than predicted for a spherical geometry. This buckling, combined with a solvent or thermal post-treatment, enables the production of dispersions of vibrant red, green, and blue cellulose photonic pigments. The hierarchical structure of these pigments enables the deposition of coatings with angular independent colour, offering a consistent visual appearance across a wide range of viewing angles.
在追求制造光子结构的可持续方法时，大自然可以为纳米结构和组成材料提供灵感。尽管已经有几种生物材料被承诺为适合光子材料和颜料的候选材料，但它们的制造过程仅限于薄膜的小到中等规模生产。在这里，通过采用无基底工艺，通过在乳化微液滴内的胆甾相纤维素纳米晶体 (CNC) 悬浮液的受限自组装来生产结构色微球。在干燥过程中，液滴经历多次屈曲事件，这使得纳米结构的收缩程度大于球形几何形状的预测。这种屈曲，再加上溶剂或热后处理，能够生产出鲜艳的红色、绿色和蓝色纤维素光子颜料的分散体。这些颜料的分层结构能够沉积具有角度无关颜色的涂层，在广泛的视角范围内提供一致的视觉外观。
