Geometry and Mechanics in the Opening of Chiral Seed Pods
Geometry and Mechanics in the Opening of Chiral Seed Pods
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DOI：
10.1126/science.1203874
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发表时间：
2011-09-23
期刊：
影响因子：
56.9
通讯作者：
Sharon, Eran
中科院分区：
文献类型：
--
作者：
Armon, Shahaf;Efrati, Efi;Sharon, Eran
我们研究了紫荆花种子荚打开的机械过程，发现了一种手性产生机制，将最初平坦的荚瓣变成螺旋形。我们研究了从荚果瓣组织和模拟其结构的复合弹性材料上切下的条带的配置。实验揭示了不同的螺旋结构，它们之间有明显的形态转变。利用“不相容弹性”的数学框架，我们将豆荚建模为具有平坦内在度规和鞍状内在曲率的薄条形。我们的理论分析定量预测了所有观察到的构型，从而将豆荚的微观结构与宏观构象联系起来。我们认为这种不相容带可能在手性大分子的自组装中发挥作用，并可用于合成自成形装置的工程。
We studied the mechanical process of seed pods opening in Bauhinia variegate and found a chirality-creating mechanism, which turns an initially flat pod valve into a helix. We studied configurations of strips cut from pod valve tissue and from composite elastic materials that mimic its structure. The experiments reveal various helical configurations with sharp morphological transitions between them. Using the mathematical framework of "incompatible elasticity," we modeled the pod as a thin strip with a flat intrinsic metric and a saddle-like intrinsic curvature. Our theoretical analysis quantitatively predicts all observed configurations, thus linking the pod's microscopic structure and macroscopic conformation. We suggest that this type of incompatible strip is likely to play a role in the self-assembly of chiral macromolecules and could be used for the engineering of synthetic self-shaping devices.