Shadpour Sasan, Nemati Ahlam, Liu Jiao, Hegmann Torsten
Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States.
Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States.
ACS Appl Mater Interfaces. 2020 Mar 18;12(11):13456-13463. doi: 10.1021/acsami.9b20696. Epub 2020 Mar 5.
In this work, we demonstrate control of the handedness of semicrystalline modulated helical nanofilaments (HNFs) 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 HNFs in the bulk, and as a result thereof do not affect the handedness or helical pitch of bulk HNFs, resulting in an HNF conglomerate with chirality-preserving growth within each domain. However, under confinement these axially chiral guest molecules, likely embedded in the HNF host, do affect the helicity of the HNFs. The configuration of the axially chiral molecules decides the HNF helix handedness and their concentration, and the helix angle is related to the helical pitch of the HNFs. In addition to local imaging data obtained by scanning electron microscopy, global studies by thin-film circular dichroism spectropolarimetry support the imaging results.
在这项工作中，我们展示了在阳极氧化铝纳米通道的空间纳米限域条件下，仅通过轴向手性联萘基添加剂作为客体分子，来控制由非手性弯曲核液晶分子形成的半结晶调制螺旋纳米丝（HNFs）的手性。相同手性添加剂的分子在本体中会从HNFs中被排出，因此不会影响本体HNFs的手性或螺旋螺距，从而形成在每个区域内具有手性保持生长的HNF聚集体。然而，在限域条件下，这些可能嵌入HNF主体中的轴向手性客体分子确实会影响HNFs的螺旋性。轴向手性分子的构型决定了HNF螺旋的手性及其浓度，并且螺旋角与HNFs的螺旋螺距相关。除了通过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整体研究也支持了成像结果。
