Photonic paper: Multiscale assembly of reflective cellulose sheets in Lunaria annua
Photonic paper: Multiscale assembly of reflective cellulose sheets in Lunaria annua
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DOI：
10.1126/sciadv.aba8966
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发表时间：
2020-07-01
期刊：
影响因子：
13.6
通讯作者：
Omenetto, F. G.
中科院分区：
文献类型：
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作者：
Guidetti, G.;Sun, H.;Omenetto, F. G.
在自然界中观察到的明亮、彩虹色通常是由纳米级周期晶格内的光干涉引起的，这激发了许多缺乏无机颜料的着色策略。在这里，我们描述和表征月月花植物的隔膜，产生大（多厘米），独立的虹彩片，具有独特的银白色反射外观。这源于隔膜细胞中纤维素纤维的薄膜组装，在微观尺度上诱导薄膜干涉样颜色，从而解释了该结构在宏观尺度上的整体银白色反射率。这些细胞进一步组装成两层薄层，形成机械坚固的彩虹色隔膜，由于细胞的空心核心结构产生的高空气孔隙率（bbb70 %），隔膜也非常轻。这种包含机械和光学功能的分层结构的组合可以激发基于鲁棒、轻和光谱响应的天然基板的设备和接口的技术类别。
Bright, iridescent colors observed in nature are often caused by light interference within nanoscale periodic lattices, inspiring numerous strategies for coloration devoid of inorganic pigments. Here, we describe and characterize the septum of the Lunaria annua plant that generates large (multicentimeter), freestanding iridescent sheets, with distinctive silvery-white reflective appearance. This originates from the thin-film assembly of cellulose fibers in the cells of the septum that induce thin-film interference-like colors at the microscale, thus accounting for the structure's overall silvery-white reflectance at the macroscale. These cells further assemble into two thin layers, resulting in a mechanically robust, iridescent septum, which is also significantly light due to its high air porosity (>70%) arising from the cells' hollow-core structure. This combination of hierarchical structure comprising mechanical and optical function can inspire technological classes of devices and interfaces based on robust, light, and spectrally responsive natural substrates.