School of Chemistry, Physics and Mechanical Engineering, Faculty of Science and Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Nat Chem. 2018 Jan;10(1):65-69. doi: 10.1038/nchem.2848. Epub 2017 Aug 28.
Single crystals are typically brittle, inelastic materials. Such mechanical responses limit their use in practical applications, particularly in flexible electronics and optical devices. Here we describe single crystals of a well-known coordination compound-copper(II) acetylacetonate-that are flexible enough to be reversibly tied into a knot. Mechanical measurements indicate that the crystals exhibit an elasticity similar to that of soft materials such as nylon, and thus display properties normally associated with both hard and soft matter. Using microfocused synchrotron radiation, we mapped the changes in crystal structure that occur on bending, and determined the mechanism that allows this flexibility with atomic precision. We show that, under strain, the molecules in the crystal reversibly rotate, and thus reorganize to allow the mechanical compression and expansion required for elasticity and still maintain the integrity of the crystal structure.
单晶通常是脆性的、无弹性的材料。这种机械响应限制了它们在实际应用中的使用，特别是在柔性电子和光学器件中。在这里，我们描述了一种众所周知的配位化合物-乙酰丙酮铜(II)的单晶，它足够柔软，可以被可逆地打成结。机械测量表明，这些晶体表现出与尼龙等软材料相似的弹性，因此表现出通常与硬物质和软物质都相关的特性。利用微聚焦同步辐射，我们绘制了在弯曲时晶体结构发生的变化，并以原子精度确定了允许这种柔韧性的机制。我们表明，在应变下，晶体中的分子可以可逆地旋转，从而重新排列，以允许弹性所需的机械压缩和扩张，并仍然保持晶体结构的完整性。
