Directing the Handedness of Helical Nanofilaments Confined in Nanochannels Using Axially Chiral Binaphthyl Dopants
Directing the Handedness of Helical Nanofilaments Confined in Nanochannels Using Axially Chiral Binaphthyl Dopants
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DOI：
10.1021/acsami.9b20696
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发表时间：
2020-03-18
影响因子：
9.5
通讯作者：
Hegmann, Torsten
中科院分区：
文献类型：
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作者：
Shadpour, Sasan;Nemati, Ahlam;Hegmann, Torsten
在这项工作中，我们证明了在阳极氧化铝纳米通道中，仅在空间纳米限制下，通过轴向手性二萘基添加剂作为客体分子，控制由非手性弯曲核液晶分子形成的半晶调制螺旋纳米丝（HNF(mod)s）的手性。具有相同手性添加剂的分子从体中的HNF(mod)s中排出，因此不会影响体HNF(mod)s的旋向性或螺旋节距，从而在每个结构域内形成具有手性保持生长的HNF（mod）团。然而，在约束条件下，这些轴向手性客体分子，可能嵌入在HNFmod宿主中，确实会影响HNF(mod)s的螺旋度。轴向手性分子的构型决定了HNF（mod）的旋向性及其浓度，螺旋角与HNF(mod)s的螺距有关。除了扫描电子显微镜获得的局部成像数据外，薄膜圆二色光谱偏振法的全局研究也支持成像结果。
In this work, we demonstrate control of the handedness of semicrystalline modulated helical nanofilaments (HNF(mod)s) formed by achiral bent-core liquid crystal molecules by axially chiral binaphthyl-based additives as guest molecules solely under spatial nanoconfinement in anodic aluminum oxide nanochannels. The molecules of the same chiral additives are expelled from the HNF(mod)s in the bulk, and as a result thereof do not affect the handedness or helical pitch of bulk HNF(mod)s, resulting in an HNFmod conglomerate with chirality-preserving growth within each domain. However, under confinement these axially chiral guest molecules, likely embedded in the HNFmod host, do affect the helicity of the HNF(mod)s. The configuration of the axially chiral molecules decides the HNFmod helix handedness and their concentration, and the helix angle is related to the helical pitch of the HNF(mod)s. In addition to local imaging data obtained by scanning electron microscopy, global studies by thin-film circular dichroism spectropolarimetry support the imaging results.