Helical Nanofilament Phases
Helical Nanofilament Phases
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DOI：
10.1126/science.1170027
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发表时间：
2009-07-24
期刊：
影响因子：
56.9
通讯作者：
Clark, N. A.
中科院分区：
文献类型：
--
作者：
Hough, L. E.;Jung, H. T.;Clark, N. A.
在手性晶体的形成中，相邻分子取向上的扭曲倾向与进入晶格的有序性是不相容的：扭曲是以局部应变为代价从平面层中排出的。我们报道了一种整齐材料的有序状态，其中局部手性结构被表示为扭曲的层，这种状态是通过将纳米级细丝的周期性阵列分层的空间限制而实现的。尽管由非手性分子组成，但这些细丝中的层是扭曲的，严格的同手性--一种打破的对称性。在灯丝自组装中实现的精确结构定义使集体能够组织成阵列，在阵列中，额外的对称性破缺--灯丝扭曲的宏观一致性的出现--产生螺旋状进行层的液晶相。
In the formation of chiral crystals, the tendency for twist in the orientation of neighboring molecules is incompatible with ordering into a lattice: Twist is expelled from planar layers at the expense of local strain. We report the ordered state of a neat material in which a local chiral structure is expressed as twisted layers, a state made possible by spatial limitation of layering to a periodic array of nanoscale filaments. Although made of achiral molecules, the layers in these filaments are twisted and rigorously homochiral-a broken symmetry. The precise structural definition achieved in filament self-assembly enables collective organization into arrays in which an additional broken symmetry-the appearance of macroscopic coherence of the filament twist-produces a liquid crystal phase of helically precessing layers.