Electro- and Photo-Driven Orthogonal Switching of a Helical Superstructure Enabled by an Axially Chiral Molecular Switch.
Electro- and Photo-Driven Orthogonal Switching of a Helical Superstructure Enabled by an Axially Chiral Molecular Switch.
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DOI：
10.1021/acsami.0c19527
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发表时间：
2020-11
影响因子：
9.5
通讯作者：
Xinfang Zhang;B. Koz;H. Bisoyi;Hao Wang;Karla G. Gutiérrez-Cuevas;M. McConney;T. Bunning;Quan Li-Quan
中科院分区：
文献类型：
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作者：
Xinfang Zhang;B. Koz;H. Bisoyi;Hao Wang;Karla G. Gutiérrez-Cuevas;M. McConney;T. Bunning;Quan Li-Quan
由特定化学结构实现的自组织功能软材料由于其刺激响应特性和在先进技术设备中的应用而目前引起了极大的关注。合成了一种新型轴向手性分子开关，在两个细长的杆状翼上含有两个偶氮键和六个末端烷基链，在非手性液晶主体中表现出优异的溶解度、高螺旋扭转能力和可逆光异构化，并用于开发光响应、自组织螺旋超结构，即胆甾型液晶（CLC）。由于基板上有表面取向层，平面 CLC 采用直立螺旋 (SH) 配置。这种SH可以转变为平躺螺旋结构，从而在电场的作用下实现可调谐衍射光栅。通过光照射调整平面 CLC 的初始间距，在施加适当的电场时产生具有平行或垂直于摩擦方向的条纹的衍射光栅。沿着正交方向的可调谐光束控制已经被证明。这种用人工手性开关制造的可调谐刺激响应软材料在光学、光子学等领域显示出巨大的潜力。
Self-organized functional soft materials, enabled by specific chemical architectures, are currently attracting tremendous attention because of their stimuli-responsive attributes and applications in advanced technological devices. A novel axially chiral molecular switch containing two azo linkages and six terminal alkyl chains on two elongated rod-shaped wings, that exhibits superior solubility, high helical twisting power, and reversible photoisomerization in an achiral liquid crystal host, is synthesized and utilized in the development of a photoresponsive, self-organized helical superstructure, that is, cholesteric liquid crystal (CLC). The planar CLC adopts a standing helix (SH) configuration because of surface alignment layers on the substrates. This SH can be transitioned to a lying helix configuration, enabling tunable diffraction gratings under the application of electric field. Adjustment of the initial pitch of the planar CLC by photoirradiation yields the diffraction gratings with stripes either parallel or perpendicular to the rubbing direction upon the application of an appropriate electric field. Tunable beam steering along orthogonal directions has been demonstrated. Such tunable stimuli-responsive soft materials fabricated with artificial chiral switches show great potential in optics, photonics, and beyond.