在自然界，一些甲虫壳由于构成甲虫外骨骼的壳质的手性组织而表现出彩虹色。受甲虫壳中所见到的设计原理的启发，Mark Maclachlan及其同事制造出了有螺旋孔的玻璃薄膜，这些螺旋孔是利用一种可再生的纤维素模板引入的。手性结构使该材料能够选择性地反射某一特定波长的光；该波长可通过在合成过程中改变二氧化硅对纤维素的比例来在整个可见光范围内调整。

该材料可以独立存在，而在吸收水后会使其结构立即变成无色，尽管颜色在该材料干后还会恢复。这些材料中手性、中孔性和光子性能的新颖组合意味着，它们在如新型涂层、智能窗户、传感器和显示器等各种不同应用中也许会有用武之地。

荐英文摘要

Nature  doi:10.1038/nature09540

Free-standing mesoporous silica films with tunable chiral nematic structures
Kevin E. Shopsowitz,Hao Qi,Wadood Y. Hamad& Mark J. MacLachlan

Chirality at the molecular level is found in diverse biological structures, such as polysaccharides, proteins and DNA, and is responsible for many of their unique properties1. Introducing chirality into porous inorganic solids may produce new types of materials that could be useful for chiral separation, stereospecific catalysis, chiral recognition (sensing) and photonic materials2, 3, 4, 5. Template synthesis of inorganic solids using the self-assembly of lyotropic liquid crystals offers access to materials with well-defined porous structures6, 7, 8, 9, 10, 11, 12, but only recently has chirality been introduced into hexagonal mesostructures through the use of a chiral surfactant13, 14. Efforts to impart chirality at a larger length scale using self-assembly are almost unknown. Here we describe the development of a photonic mesoporous inorganic solid that is a cast of a chiral nematic liquid crystal formed from nanocrystalline cellulose. These materials may be obtained as free-standing films with high surface area. The peak reflected wavelength of the films can be varied across the entire visible spectrum and into the near-infrared through simple changes in the synthetic conditions. To the best of our knowledge these are the first materials to combine mesoporosity with long-range chiral ordering that produces photonic properties. Our findings could lead to the development of new materials for applications in, for example, tuneable reflective filters and sensors. In addition, this type of material could be used as a hard template to generate other new materials with chiral nematic structures.