Department of Materials System Science, Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, Kanagawa, 236-0027, Japan.
Kanagawa Institute of Industrial Science and Technology, Shimoimaizumi, 705-1 Ebina, Kanagawa, 243-0435, Japan.
Angew Chem Int Ed Engl. 2017 Dec 11;56(50):15882-15885. doi: 10.1002/anie.201707749. Epub 2017 Nov 2.
Ferroelasticity has been relatively well-studied in mechanically robust inorganic atomic solids but poorly investigated in organic crystals, which are typically inherently fragile. The absence of precise methods for the mechanical analysis of small crystals has, no doubt, impeded research on organic ferroelasticity. The first example of ferroelasticity in an organic molecular crystal of 5-chloro-2-nitroaniline is presented, with thorough characterization by macro- and microscopic methods. The observed cyclic stress-strain curve satisfies the requirements of ferroelasticity. Single-crystal X-ray structure analysis provides insight into lattice correspondence at the twining interface, which enables substantial crystal bending by a large molecular orientational shift. This deformation represents the highest maximum strain (115.9 %) among reported twinning materials, and the associated dissipated energy density of 216 kJ m is relatively large, which suggests that this material is potentially useful as a mechanical damping agent.
铁弹性在机械坚固的无机原子固体中得到了较为充分的研究，但在通常固有脆弱的有机晶体中研究甚少。缺乏对小晶体进行机械分析的精确方法，无疑阻碍了对有机铁弹性的研究。本文首次提出了 5-氯-2-硝基苯胺有机分子晶体中存在铁弹性的实例，并通过宏观和微观方法进行了彻底的特征描述。观察到的循环应力-应变曲线满足铁弹性的要求。单晶 X 射线结构分析深入了解了孪晶界面处的晶格对应关系，这使得通过大的分子取向转变实现了大量晶体弯曲。这种变形代表了已报道的孪晶材料中的最大应变（115.9%），相关的耗散能量密度为 216kJ/m，相对较大，这表明该材料作为机械阻尼剂具有潜在的用途。
